Year 5: Comparing two values on a line graph
Part of the Year 5 statistics chapter. Chapter overview · whole chapter on one page
Comparing two values on a line graph
A comparison problem asks how much more or how much less one value is than another. Read both values from the graph, then subtract the smaller value from the bigger one.
When a graph has two lines, compare the two points at the same time or week. Look at the key to see which line is which.
Key ideas
- A comparison asks how much more or how much less: subtract to find the difference.
- Compare the two lines at the same time or week, then say which value is bigger.
- Read the key before you read the graph, so you know which line belongs to which name.
- The difference is always found by taking the smaller value away from the bigger one.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both values, then subtract the smaller one from the bigger one.
- Read the value for Aisha's plant in Week 4. Find the point on the line and read across to the scale.18 cm
- Read the value for Leo's plant in Week 4. Do the same for the second point.16 cm
- Subtract the smaller value from the bigger value. The difference tells you how much more one value is than the other.18 − 16 = 2
- Write the answer. 2 cm
Check. 16 + 2 = 18, so the difference is right. ✓
Watch out. Always subtract the smaller value from the bigger one, so the answer is not negative.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both values, then subtract the smaller one from the bigger one.
- Read the value for 13:00. Find the point on the line and read across to the scale.14 °C
- Read the value for 09:00. Do the same for the second point.6 °C
- Subtract the smaller value from the bigger value. The difference tells you how much more one value is than the other.14 − 6 = 8
- Write the answer. 8 °C
Check. 6 + 8 = 14, so the difference is right. ✓
Watch out. Always subtract the smaller value from the bigger one, so the answer is not negative.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both values, then subtract the smaller one from the bigger one.
- Read the value for Saturday. Find the point on the line and read across to the scale.11,000 steps
- Read the value for Wednesday. Do the same for the second point.5,000 steps
- Subtract the smaller value from the bigger value. The difference tells you how much more one value is than the other.11,000 − 5,000 = 6,000
- Write the answer. 6,000 steps
Check. 5,000 + 6,000 = 11,000, so the difference is right. ✓
Watch out. Always subtract the smaller value from the bigger one, so the answer is not negative.
Watch out
Watch out: the bigger value goes first in your subtraction, so the answer is never negative. Also check that you have compared the same week on both lines, not two different weeks.
Exercise 11B Comparing values on a line graph
Non-calculatorKey words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both values, then subtract the smaller one from the bigger one.
- Read the value for Leo's plant in Week 3. Find the point on the line and read across to the scale.14 cm
- Read the value for Aisha's plant in Week 3. Do the same for the second point.12 cm
- Subtract the smaller value from the bigger value. The difference tells you how much more one value is than the other.14 − 12 = 2
- Write the answer. 2 cm
Check. 12 + 2 = 14, so the difference is right. ✓
Watch out. Always subtract the smaller value from the bigger one, so the answer is not negative.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both values, then subtract the smaller one from the bigger one.
- Read the value for Aisha's plant in Week 6. Find the point on the line and read across to the scale.26 cm
- Read the value for Leo's plant in Week 6. Do the same for the second point.24 cm
- Subtract the smaller value from the bigger value. The difference tells you how much more one value is than the other.26 − 24 = 2
- Write the answer. 2 cm
Check. 24 + 2 = 26, so the difference is right. ✓
Watch out. Always subtract the smaller value from the bigger one, so the answer is not negative.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both values, then subtract the smaller one from the bigger one.
- Read the value for Aisha's plant in Week 5. Find the point on the line and read across to the scale.22 cm
- Read the value for Leo's plant in Week 5. Do the same for the second point.16 cm
- Subtract the smaller value from the bigger value. The difference tells you how much more one value is than the other.22 − 16 = 6
- Write the answer. 6 cm
Check. 16 + 6 = 22, so the difference is right. ✓
Watch out. Always subtract the smaller value from the bigger one, so the answer is not negative.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Work out the gap for every week, then choose the biggest one.
- Find the gap in each week. The gap is the bigger height minus the smaller height.Week 1: 2 cm, Week 2: 2 cm, Week 3: 2 cm, Week 4: 2 cm, Week 5: 6 cm, Week 6: 2 cm
- Find the biggest gap. Only Week 5 has a gap of 6 cm. Every other week has a smaller gap.biggest gap = 6 cm
- Write the answer. Week 5, a gap of 6 cm
Check. In Week 5, 22 − 16 = 6. ✓
Watch out. The gap is always a positive number. Do not say a gap is negative.
Method. Compare the two heights in each week, then count the weeks when Aisha's plant is taller.
- Compare the two plants in each week. Look for the weeks when Aisha's line is higher.Week 1: 4 > 2, Week 2: 8 > 6, Week 3: 12 < 14, Week 4: 18 > 16, Week 5: 22 > 16, Week 6: 26 > 24
- Count the weeks when Aisha was taller. Count only the weeks where her value is the bigger one.1, 2, 4, 5, 6
- Write the answer. 5 weeks
Check. The weeks when Leo was taller are the ones left, so 5 + 1 = 6 weeks. ✓
Watch out. Compare the two plants in the same week. A week is not counted twice.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both values, then subtract the smaller one from the bigger one.
- Read the value for 13:00. Find the point on the line and read across to the scale.14 °C
- Read the value for 10:00. Do the same for the second point.8 °C
- Subtract the smaller value from the bigger value. The difference tells you how much more one value is than the other.14 − 8 = 6
- Write the answer. 6 °C
Check. 8 + 6 = 14, so the difference is right. ✓
Watch out. Always subtract the smaller value from the bigger one, so the answer is not negative.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both temperatures, then compare them.
- Read the temperature at 11:00. Go up from 11:00 to the line.10 °C
- Read the temperature at 15:00. Go up from 15:00 to the line.10 °C
- Compare them. If the two values are the same, neither is warmer.10 − 10 = 0
- Write the answer. The two temperatures are the same, so there is no difference.0 °C
Check. The line is at the same height at both times. ✓
Watch out. A difference of 0 means the two values are equal.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both values, then subtract the smaller one from the bigger one.
- Read the value for Friday. Find the point on the line and read across to the scale.7,000 steps
- Read the value for Monday. Do the same for the second point.6,000 steps
- Subtract the smaller value from the bigger value. The difference tells you how much more one value is than the other.7,000 − 6,000 = 1,000
- Write the answer. 1,000 steps
Check. 6,000 + 1,000 = 7,000, so the difference is right. ✓
Watch out. Always subtract the smaller value from the bigger one, so the answer is not negative.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Start from Wednesday, add 2,000, then find the day with that many steps.
- Read the steps on Wednesday. Go up from Wednesday to the line.5,000 steps
- Add 2,000 steps. We want a day with 2,000 more steps than Wednesday.5,000 + 2,000 = 7,000
- Find 7,000 steps on the scale. Go across from 7,000 to the line, then down to the bottom.the point at 7,000 is on Friday
- Write the answer. Friday
Check. Friday is the only point at 7,000 steps, and 7,000 − 5,000 = 2,000. ✓
Watch out. To find a value that is 2,000 more, add 2,000 to the starting value. Then check the line at that height.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both values, then subtract the smaller one from the bigger one.
- Read the value for Thursday. Find the point on the line and read across to the scale.9,000 steps
- Read the value for Tuesday. Do the same for the second point.8,000 steps
- Subtract the smaller value from the bigger value. The difference tells you how much more one value is than the other.9,000 − 8,000 = 1,000
- Write the answer. 1,000 steps
Check. 8,000 + 1,000 = 9,000, so the difference is right. ✓
Watch out. Always subtract the smaller value from the bigger one, so the answer is not negative.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both values, then subtract the smaller one from the bigger one.
- Read the value for Sunday. Find the point on the line and read across to the scale.10,000 steps
- Read the value for Wednesday. Do the same for the second point.5,000 steps
- Subtract the smaller value from the bigger value. The difference tells you how much more one value is than the other.10,000 − 5,000 = 5,000
- Write the answer. 5,000 steps
Check. 5,000 + 5,000 = 10,000, so the difference is right. ✓
Watch out. Always subtract the smaller value from the bigger one, so the answer is not negative.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Read both values, then subtract the smaller one from the bigger one.
- Read the value for Saturday. Find the point on the line and read across to the scale.11,000 steps
- Read the value for Thursday. Do the same for the second point.9,000 steps
- Subtract the smaller value from the bigger value. The difference tells you how much more one value is than the other.11,000 − 9,000 = 2,000
- Write the answer. 2,000 steps
Check. 9,000 + 2,000 = 11,000, so the difference is right. ✓
Watch out. Always subtract the smaller value from the bigger one, so the answer is not negative.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Find the difference that Ali is talking about, then check his number.
- Read the temperature at 10:00. Ali is comparing 13:00 with 10:00.8 °C
- Read the temperature at 13:00. Go up from 13:00 to the line.14 °C
- Find the real difference. Subtract the smaller value from the bigger one.14 − 8 = 6
- Compare with Ali's number. Ali said 4, but the difference is 6.6 is not 4
Check. 8 + 6 = 14, so the difference is 6 °C. ✓
Watch out. Check your subtraction by adding the difference to the smaller value.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Find both plants in Week 3 and compare them.
- Read Leo's plant in Week 3. Go up from Week 3 to Leo's line.14 cm
- Read Aisha's plant in Week 3. Go up from Week 3 to Aisha's line.12 cm
- Subtract the smaller value from the bigger one. The difference is how much taller Leo's plant was.14 − 12 = 2
- Write the answer. Yes, Leo is right: 2 cm taller
Check. 12 + 2 = 14, so Leo's plant was 2 cm taller. ✓
Watch out. Read the line for each plant, not the line above or below.
Key words. A comparison says how much more or how much less one value is than another. The difference is found by subtracting the smaller value from the bigger one.
Method. Look for a week where the gap is more than 2 cm.
- Look at Week 5. Week 5 is a week where the two lines are far apart.22 cm and 16 cm
- Subtract the smaller value from the bigger one. The gap is the difference.22 − 16 = 6
- Decide. A gap of 6 cm is more than 2 cm, so Aisha is wrong.No
Check. 16 + 6 = 22, so the gap in Week 5 is 6 cm. ✓
Watch out. One week is enough to show a statement is false.