Year 4 Telling the Time and the 24-Hour Clock: check-up and SATs-style questions

Key words. An analogue clock has a round face with two hands. The short, thick hour hand shows the hour. The long, thin minute hand shows the minutes. Past means after the hour. To means before the next hour.

Method. Look at the hour hand first, then the minute hand. Count the minutes in fives, then say the time.

1. Look at the short hand (the hour hand). It tells us the hour. Use the last number it has passed.
   The short hand is between 8 and 9. It has passed 8 but has not reached 9, so the hour is 8.
2. Look at the long hand (the minute hand). It tells us the minutes. Count in fives from the 12, then count single marks.
   The long hand points at 7. Count in fives: 5, 10, 15, 20, 25, 30, 35.
   7 × 5 = 35 minutes
3. Say the time. Use the minutes to say past or to, and the hour from step 1.
   The minute hand is on the left-hand side, so we say to. We count the minutes to the next hour.
   60 − 35 = 25 minutes to 9.
   twenty-five to nine

Check. In numbers this is 8:35. ✓

Watch out. Use the hour the short hand has passed, even when the minute hand is nearly round to the next hour.

Key words. An analogue clock has a round face with two hands. The short, thick hour hand shows the hour. The long, thin minute hand shows the minutes. Past means after the hour. To means before the next hour.

Method. The short hand gives the hour and the long hand gives the minutes. Write them with a colon between.

1. Look at the short hand (the hour hand). It tells us the hour. Use the last number it has passed.
   The short hand is between 4 and 5. It has passed 4 but has not reached 5, so the hour is 4.
2. Look at the long hand (the minute hand). It tells us the minutes. Count in fives from the 12, then count single marks.
   The long hand has passed the 3 and is 3 small marks further on.
   The 3 is 3 × 5 = 15 minutes. Now count on 3.
   15 + 3 = 18 minutes
3. Write the time in numbers. A digital time is the hour, a colon, then the minutes. The minutes always have two digits.
   hour 4, minutes 18 → 4:18

Check. In words this is eighteen minutes past four. ✓

Watch out. Do not mix up the two hands. The short, thick hand shows the hour. The long, thin hand shows the minutes.

Key words. A digital clock shows the time in numbers: hours, a colon, then minutes (7:45). am is for times between midnight and noon (the morning). pm is for times between noon and midnight (the afternoon and evening). The 24-hour clock counts the hours from 00 to 23 and does not use am or pm.

Method. For am times the hour stays the same (12 am becomes 00). For pm times add 12 to the hour (12 pm stays 12).

1. Look at am or pm: 5:40 pm. This tells us which rule to use.
   5:40 pm
2. Add 12 to the hour. For pm times the 24-hour clock carries on counting after 12.
   5 + 12 = 17
3. Write the 24-hour time. Two digits for the hour, a colon, two digits for the minutes.
   17:40

Check. Change back: 17:40 is 5:40 pm. ✓

Watch out. Do not add 12 to a morning time, and do not add 12 to 12 pm.

Key words. A digital clock shows the time in numbers: hours, a colon, then minutes (7:45). am is for times between midnight and noon (the morning). pm is for times between noon and midnight (the afternoon and evening). The 24-hour clock counts the hours from 00 to 23 and does not use am or pm.

Method. Before 12:00 it is am and the hour stays. From 13:00 take 12 away and use pm.

1. Look at the hour in 21:15. It tells us whether it is morning or afternoon.
   The hour is 21.
2. Take 12 away from the hour. After 12:00 the 24-hour clock goes 13, 14, 15... and the 12-hour clock goes 1, 2, 3... with pm.
   21 − 12 = 9 pm
3. Write the 12-hour time. Use the colon and the minutes, then am or pm.
   9:15 pm

Check. Change back: 9:15 pm is 21:15. ✓

Watch out. Midnight is 00:00. 24:00 is the same moment at the end of the day.

Key words. To convert is to change from one unit to another. 60 seconds = 1 minute. 60 minutes = 1 hour. 24 hours = 1 day. 7 days = 1 week. 12 months = 1 year. To go from a big unit to a small unit we multiply. To go from a small unit to a big unit we divide.

Method. There are 60 minutes in 1 h. Going from hours to minutes (big unit to small unit), we multiply by 60.

1. Write the fact. We need to know how many of the small unit make one of the big unit.
   1 h = 60 minutes
2. Multiply by 60. We have 7 hours, so we need 7 lots of 60.
   7 × 60 = 7 × 6 × 10 = 42 × 10 = 420
3. Write the answer with its unit.
   7 hours = 420 minutes

Check. Go back: 420 ÷ 60 = 7. ✓

Watch out. A big unit changes to a bigger number of small units. 7 hours must be more than 7 minutes.

Key words. To convert is to change from one unit to another. 60 seconds = 1 minute. 60 minutes = 1 hour. 24 hours = 1 day. 7 days = 1 week. 12 months = 1 year. To go from a big unit to a small unit we multiply. To go from a small unit to a big unit we divide.

Method. There are 60 seconds in 1 min. Going from seconds to minutes (small unit to big unit), we divide by 60.

1. Write the fact. We need to know how many of the small unit make one of the big unit.
   1 min = 60 seconds
2. Divide by 60. Going from seconds to minutes (small unit to big unit) we divide. We find how many lots of 60 are in 180.
   180 ÷ 60 = 18 ÷ 6 = 3 (divide by 10, then by 6)
3. Write the answer with its unit.
   180 seconds = 3 minutes

Check. 3 × 60 = 180 = 180. ✓

Watch out. A small unit changes to a smaller number of big units. 180 seconds must be fewer than 180 minutes.

Key words. A calendar shows the days and dates of the months. A leap year has 366 days instead of 365, because February has 29 days. Date means the day of the month (like 14 March).

Method. Use your knuckles. Each knuckle is a month with 31 days. Each dip between knuckles is a month with 30 days (except February).

1. Make a fist and say the months, starting on the first knuckle. August is a knuckle too: after July go back to the first knuckle and start again.
   Aug: knuckle
   Sep: dip
   Oct: knuckle
   Nov: dip
2. Find out if November is a knuckle or a dip. Knuckle: 31 days. Dip: 30 days. February is the odd one out.
   November is a dip: 30 days.
3. Write the answer.
   November has 30 days.

Check. The rhyme way: April, June, September and November have 30. February has 28 or 29. All the rest have 31. ✓

Watch out. February is the only month that does not have 30 or 31 days.

Key words. The duration is how long something takes (how much time goes by). To count on is to jump forward from one time to another. The start time is when something begins. The end time is when it finishes.

Method. Count on from the start to the end on a number line: first to the next o'clock, then in whole hours, then the last minutes. Then add the jumps.

1. Draw a number line and count on from the start time to the end time. Counting on in easy jumps (first to the next o'clock, then whole hours, then the last minutes) is easier than taking one time away from the other.
2. Work out each jump. Each jump is easy to do in your head.
   4:35 pm to 5:00 pm: 25 minutes to the next o'clock
   60 − 35 = 25 minutes
   5:00 pm to 5:20 pm: the minutes after the o'clock: 20 minutes
3. Add the jumps. Add the hours together, then add the minutes together. If the minutes reach 60 or more, change 60 minutes into 1 hour.
   Minutes: 25 + 20 = 45
   Total: 45 minutes

Check. Count on from the start: 4:35 pm + 45 minutes = 5:20 pm. ✓

Watch out. There are 60 minutes in an hour, not 100. 3:50 to 4:20 is 30 minutes, not 70.

Key words. The duration is how long something takes (how much time goes by). To count on is to jump forward from one time to another. The start time is when something begins. The end time is when it finishes.

Method. Add the whole hours first. Then add the minutes, jumping to the next o'clock if you pass it.

1. Start at the start time and count on the whole hours first. Adding whole hours is easy: the minutes stay the same.
   10:40 am + 1 hour = 11:40 am
2. Count on the 35 minutes. Going to the next o'clock first makes the sum easy. The minutes left are added after.
   Jump to the next o'clock: 60 − 40 = 20 minutes, so 11:40 am + 20 min = 12:00 pm.
   Jump the rest: 35 − 20 = 15 minutes, so 12:00 pm + 15 min = 12:15 pm
3. Look at the number line. It shows all the jumps from the start to the end.
4. Write the end time.
   12:15 pm

Check. Count back from the end: 12:15 pm − 1 hour 35 minutes = 10:40 am. ✓

Watch out. The minutes go up to 60, then the hour changes. 2:45 + 30 minutes is 3:15, not 2:75.

Key words. The duration is how long something takes (how much time goes by). To count on is to jump forward from one time to another. The start time is when something begins. The end time is when it finishes.

Method. Count on from the start to the end on a number line: first to the next o'clock, then in whole hours, then the last minutes. Then add the jumps.

1. Look along the row for Park. We want the first bus that leaves at or after the time you arrive. A bus that has already gone is no use.
   08:10, 08:40, 09:12, 09:55
2. Choose the first bus that is not too early. You arrive at 08:20.
   The next bus is Bus 2 at 08:40.
3. Draw a number line and count on from the start time to the end time. Counting on in easy jumps (first to the next o'clock, then whole hours, then the last minutes) is easier than taking one time away from the other.
4. Work out each jump. Each jump is easy to do in your head.
   08:20 to 08:40: 40 − 20 = 20 minutes
5. Add the jumps. Add the hours together, then add the minutes together. If the minutes reach 60 or more, change 60 minutes into 1 hour.
   Minutes: 20
   Total: 20 minutes

Check. Count on from the start: 08:20 + 20 minutes = 08:40. ✓

Watch out. A bus that left before you arrived does not count, even if it is the closest time.

Key words. An analogue clock has a round face with two hands. The short, thick hour hand shows the hour. The long, thin minute hand shows the minutes. Past means after the hour. To means before the next hour.

Method. The short hand gives the hour and the long hand gives the minutes. Write them with a colon between.

1. Look at the short hand (the hour hand). It tells us the hour. Use the last number it has passed.
   The short hand is between 8 and 9. It has passed 8 but has not reached 9, so the hour is 8.
2. Look at the long hand (the minute hand). It tells us the minutes. Count in fives from the 12, then count single marks.
   The long hand points at 5. Count in fives: 5, 10, 15, 20, 25.
   5 × 5 = 25 minutes
3. Write the time in numbers. A digital time is the hour, a colon, then the minutes. The minutes always have two digits.
   hour 8, minutes 25 → 8:25

Check. In words this is twenty-five past eight. ✓

Watch out. Do not mix up the two hands. The short, thick hand shows the hour. The long, thin hand shows the minutes.

Key words. An analogue clock has a round face with two hands. The short, thick hour hand shows the hour. The long, thin minute hand shows the minutes. Past means after the hour. To means before the next hour.

Method. Work out where both hands should be. Then check each clock.

1. Say the time we want: 3:40, which is twenty to four. We need the hour and the minutes in numbers.
   3:40
2. Find where the minute hand should point. The long hand shows the minutes.
   The minute hand points at the 8 (8 × 5 = 40 minutes).
3. Find where the hour hand should be. The short hand shows the hour.
   The hour hand is between 3 and 4 (it has passed 3).
4. Check each clock. Read each clock. The right one has both hands in the right places.
   A: shows 3:20 × not a match
   B: shows 8:15 × not a match
   C: shows 3:40 ✓
   D: shows 7:40 × not a match
5. Choose the clock.
   C

Check. Clock C has the minute hand at 40 minutes and the hour hand past 3. ✓

Watch out. A clock with the hands the wrong way round (short hand for minutes) shows a different time.

Key words. A digital clock shows the time in numbers: hours, a colon, then minutes (7:45). am is for times between midnight and noon (the morning). pm is for times between noon and midnight (the afternoon and evening). The 24-hour clock counts the hours from 00 to 23 and does not use am or pm.

Method. For am times the hour stays the same (12 am becomes 00). For pm times add 12 to the hour (12 pm stays 12).

1. Look at am or pm: 6:45 pm. This tells us which rule to use.
   6:45 pm
2. Add 12 to the hour. For pm times the 24-hour clock carries on counting after 12.
   6 + 12 = 18
3. Write the 24-hour time. Two digits for the hour, a colon, two digits for the minutes.
   18:45

Check. Change back: 18:45 is 6:45 pm. ✓

Watch out. Do not add 12 to a morning time, and do not add 12 to 12 pm.

Key words. To convert is to change from one unit to another. 60 seconds = 1 minute. 60 minutes = 1 hour. 24 hours = 1 day. 7 days = 1 week. 12 months = 1 year. To go from a big unit to a small unit we multiply. To go from a small unit to a big unit we divide.

Method. There are 60 minutes in 1 h. Going from hours to minutes (big unit to small unit), we multiply by 60.

1. Write the fact. We need to know how many of the small unit make one of the big unit.
   1 h = 60 minutes
2. Multiply by 60. We have 4 hours, so we need 4 lots of 60.
   4 × 60 = 4 × 6 × 10 = 24 × 10 = 240
3. Write the answer with its unit.
   4 hours = 240 minutes

Check. Go back: 240 ÷ 60 = 4. ✓

Watch out. A big unit changes to a bigger number of small units. 4 hours must be more than 4 minutes.

Key words. To convert is to change from one unit to another. 60 seconds = 1 minute. 60 minutes = 1 hour. 24 hours = 1 day. 7 days = 1 week. 12 months = 1 year. To go from a big unit to a small unit we multiply. To go from a small unit to a big unit we divide.

Method. Change every time to minutes, because 2 hours 30 minutes is 150 minutes. Then find the ones equal to 150 minutes.

1. Change 2 hours 30 minutes to minutes. 2 hours = 2 × 60 minutes.
   2 × 60 = 120, and 120 + 30 = 150 minutes
2. Check each option. We want the ones that are 150 minutes.
   A: 150 minutes ✓
   B: 230 minutes is more than 150 minutes
   C: 2.5 hours = 2 hours and a half hour = 120 + 30 = 150 minutes ✓
   D: 2 hours 50 minutes = 120 + 50 = 170 minutes
3. Choose the two.
   A and C

Check. Both A and C are 150 minutes. ✓

Watch out. 2.5 hours is 2 hours 30 minutes. An hour has 60 minutes, so 2 hours 50 minutes is a different time.

Key words. A calendar shows the days and dates of the months. A leap year has 366 days instead of 365, because February has 29 days. Date means the day of the month (like 14 March).

Method. A leap year can be divided by 4 with nothing left over. To check, divide the last two digits by 4.

1. Look at the last two digits of 2036. Because 100 divides exactly by 4, only the last two digits matter.
   The last two digits are 36.
2. Divide 36 by 4. If there is no remainder, the number is in the 4 times table.
   4 × 9 = 36. 36 ÷ 4 = 9 exactly.
3. Decide.
   2036 can be divided by 4 exactly, so it is a leap year. Yes

Check. 4 × 509 = 2,036 = 2036. ✓

Watch out. A leap year has 366 days, and February has 29 days.

Key words. The duration is how long something takes (how much time goes by). To count on is to jump forward from one time to another. The start time is when something begins. The end time is when it finishes.

Method. Count on from the start to the end on a number line: first to the next o'clock, then in whole hours, then the last minutes. Then add the jumps.

1. Draw a number line and count on from the start time to the end time. Counting on in easy jumps (first to the next o'clock, then whole hours, then the last minutes) is easier than taking one time away from the other.
2. Work out each jump. Each jump is easy to do in your head.
   4:50 pm to 5:00 pm: 10 minutes to the next o'clock
   60 − 50 = 10 minutes
   5:00 pm to 5:35 pm: the minutes after the o'clock: 35 minutes
3. Add the jumps. Add the hours together, then add the minutes together. If the minutes reach 60 or more, change 60 minutes into 1 hour.
   Minutes: 10 + 35 = 45
   Total: 45 minutes

Check. Count on from the start: 4:50 pm + 45 minutes = 5:35 pm. ✓

Watch out. There are 60 minutes in an hour, not 100. 3:50 to 4:20 is 30 minutes, not 70.

Key words. The duration is how long something takes (how much time goes by). To count on is to jump forward from one time to another. The start time is when something begins. The end time is when it finishes.

Method. Add the whole hours first. Then add the minutes, jumping to the next o'clock if you pass it.

1. Start at the start time and count on the whole hours first. Adding whole hours is easy: the minutes stay the same.
   10:35 pm + 8 hours = 6:35 am
2. Count on the 50 minutes. Going to the next o'clock first makes the sum easy. The minutes left are added after.
   Jump to the next o'clock: 60 − 35 = 25 minutes, so 6:35 am + 25 min = 7:00 am.
   Jump the rest: 50 − 25 = 25 minutes, so 7:00 am + 25 min = 7:25 am
3. Look at the number line. It shows all the jumps from the start to the end.
4. Write the end time.
   7:25 am

Check. Count back from the end: 7:25 am − 8 hours 50 minutes = 10:35 pm. ✓

Watch out. The minutes go up to 60, then the hour changes. 2:45 + 30 minutes is 3:15, not 2:75.

Key words. A timetable is a table that shows times. Each row goes across and each column goes down. The journey time is how long the trip takes. The waiting time is how long you wait.

Method. Find the next bus at the Market after 08:20. Count on to find how long Jack waits. Then read when that bus gets to the Station.

1. Find the next bus. Look along the Market row for the first time that is at or after 08:20.
   Market: 07:58 (gone), 08:28, 08:58, 09:43. The next bus is Bus 2 at 08:28.
2. Work out the waiting time. Count on from 08:20 to 08:28.
   08:28 − 08:20 = 8 minutes
3. Find when Bus 2 arrives at the Station. Look in the Station row, Bus 2 column.
   Bus 2 arrives at the Station at 08:54.

Check. 08:20 + 8 minutes = 08:28. ✓

Watch out. The 07:58 bus has already gone. Use the Bus 2 column all the way down.

Key words. To convert is to change from one unit to another. 60 seconds = 1 minute. 60 minutes = 1 hour. 24 hours = 1 day. 7 days = 1 week. 12 months = 1 year. To go from a big unit to a small unit we multiply. To go from a small unit to a big unit we divide.

Method. Change the fraction of an hour into minutes. Then add. Then compare with what Amira said.

1. Find a quarter of an hour. An hour is 60 minutes. A quarter is 60 ÷ 4.
   60 ÷ 4 = 15 minutes
2. Write 2¼ hours in hours and minutes. 2 whole hours and a quarter of an hour.
   2 hours and 15 minutes
3. Compare with Amira. She said 2 hours 25 minutes.
   15 is not 25. Amira is not right. The correct time is 2 hours 15 minutes.

Check. 2 hours 15 minutes = 120 + 15 = 135 minutes, and 2¼ hours = 2 × 60 + 15 = 135. ✓

Watch out. A quarter of an hour is 15 minutes (not 25).