Year 1 Adding and Subtracting within 10: check-up and quiz

Key words. To add is to put groups together. Count on means keep going up from a number.

Method. Start at the bigger number, then count on the smaller number.

1. Start at the bigger number, 4. It is quicker to start with the bigger number.
   Start: 4
2. Count on 3 more. Say one number for each step on.
   4, then 5, 6, 7
3. Write the total. The last number you say is the total.
   7

Check. Count all 7 things one at a time. You get 7 again. ✓

Watch out. Do not say the starting number again. Start with the next number after it.

Key words. To count back is to go down one number at a time.

Method. Start at the bigger number. Count back one at a time. The number you land on is the answer.

1. Start at 9 on the number line. Put your finger on the start number.
   Start: 9
2. Count back 5. Each step back is one less than the number before.
   8, 7, 6, 5, 4
3. Write the number you land on. The last number you say is the answer.
   4

Check. Count on from 4 to 9: that is 5 steps. ✓

Watch out. Do not count the starting number as your first step back.

Key words. Take away means remove some. The − sign means take away.

Method. Start with all the things. Cross out the ones taken away, then count what is left.

1. Start with all the things. Count the whole group first.
   Start: 6
2. Take away (cross out) the ones that go. Taking away means removing some.
   6 − 2
3. Count what is left. Count only the things that are not crossed out.
   4 left
4. Write the answer.
   4

Check. Add back what you took away: 4 + 2 = 6. ✓

Watch out. Count only the things that are left. Do not count the crossed-out ones.

Key words. A missing number is shown by a box. Find the number that makes the sentence true.

Method. Start at 6. Count on until you reach 10. The number of counts is the missing number.

1. Start at 6, the number we know. Put your finger on it.
   Start: 6
2. Count on to 10. Say each number as you count on.
   7, 8, 9, 10
3. Count how many numbers you said. That many is the missing number.
   4 numbers
4. Write the missing number.
   4

Check. 6 + 4 = 10. ✓

Watch out. Count the numbers after 6, not 6 itself.

Key words. The + sign means add. The = sign means the answer is.

Method. Count each group. Then join them with a + sign and write the total after an = sign.

1. Count the first group. Say how many there are.
   3
2. Count the second group. Say how many there are in the other group.
   5
3. Join the groups with the + sign. The + sign shows that we put them together.
   3 + 5
4. Write the whole sentence. The = sign comes before the total.
   3 + 5 = 8

Check. Count all the things in both groups: 8. ✓

Watch out. Put the + sign between the two groups, and the = sign before the total.

Key words. A missing number is shown by a box. Find the number that makes the sentence true.

Method. Start at 6. Count on until you reach 9. The number of counts is the missing number.

1. Start at 6, the number we know. Put your finger on it.
   Start: 6
2. Count on to 9. Say each number as you count on.
   7, 8, 9
3. Count how many numbers you said. That many is the missing number.
   3 numbers
4. Write the missing number.
   3

Check. 6 + 3 = 9. ✓

Watch out. Count the numbers after 6, not 6 itself.

Key words. Adding undoes taking away.

Method. Undo the take away. Put back the number that was taken away.

1. Look at the answer, 8. The answer is what is left after taking away.
   Answer: 8
2. Add 2 back on. Adding undoes taking away.
   8 + 2 = 10
3. Write the missing number.
   10

Check. 10 − 2 = 8. ✓

Watch out. Do not take the number away again. Put it back on instead.

Key words. Zero means none at all.

Method. Start with zero things. Then add the things.

1. Start with zero. Zero means there are no things yet.
   0
2. Add 5. Now there are 5 things.
   0 + 5
3. Write the answer. The total is the number you added.
   5

Check. Count 5 things. ✓

Watch out. Zero on the left still means none. The answer is the other number.

Key words. Take away means some things go away. The − sign shows it.

Method. Read the story. Decide if we add or take away. Then write one number sentence.

1. Find the two numbers in the story. Start with the number we had.
   7 and 3
2. Decide: add or take away? Things going away means take away.
   Going away, so we take away
3. Write the number sentence. The sentence shows the story.
   7 − 3 = 4
4. Write the answer. Say what the number is for.
   4 cars

Check. Add back the 3 that went: 4 + 3 = 7. ✓

Watch out. Start with the number you had at the beginning, not the number that went away.

Key words. A fact family is a set of sentences that use the same three numbers.

Method. Use the same three numbers. Swap the parts for the second addition. Take each part away from the whole for the subtractions.

1. Find the whole and the two parts. The whole is the biggest number.
   Whole 9, parts 2 and 7
2. Write the two addition sentences. Swap the parts round for the second one.
   2 + 7 = 9 and 7 + 2 = 9
3. Write the two subtraction sentences. Take each part away from the whole.
   9 − 2 = 7 and 9 − 7 = 2
4. Write the whole family.
   2 + 7 = 9, 7 + 2 = 9, 9 − 2 = 7, 9 − 7 = 2

Check. Check: 2 + 7 = 9 and 9 − 7 = 2. ✓

Watch out. In a subtraction sentence the whole always comes first.

Key words. To add is to put groups together. Count on means keep going up from a number.

Method. Start at the bigger number, then count on the smaller number.

1. Start at the bigger number, 6. It is quicker to start with the bigger number.
   Start: 6
2. Count on 2 more. Say one number for each step on.
   6, then 7, 8
3. Write the total. The last number you say is the total.
   8

Check. Count all 8 things one at a time. You get 8 again. ✓

Watch out. Do not say the starting number again. Start with the next number after it.

Key words. To count back is to go down one number at a time.

Method. Start at the bigger number. Count back one at a time. The number you land on is the answer.

1. Start at 10 on the number line. Put your finger on the start number.
   Start: 10
2. Count back 3. Each step back is one less than the number before.
   9, 8, 7
3. Write the number you land on. The last number you say is the answer.
   7

Check. Count on from 7 to 10: that is 3 steps. ✓

Watch out. Do not count the starting number as your first step back.

Key words. To add is to put groups together. Count on means keep going up from a number.

Method. Start at the bigger number, then count on the smaller number.

1. Start at the bigger number, 4. It is quicker to start with the bigger number.
   Start: 4
2. Count on 3 more. Say one number for each step on.
   4, then 5, 6, 7
3. Write the total. The last number you say is the total.
   7

Check. Count all 7 things one at a time. You get 7 again. ✓

Watch out. Do not say the starting number again. Start with the next number after it.

Key words. The − sign means take away. The answer is after the = sign.

Method. Start with the whole. Take away the part that goes. Write the sentence.

1. Start with the whole. Count everything at the start.
   Start: 5
2. Take away the part that goes. The − sign means take away.
   5 − 2
3. Count what is left and write the sentence. The answer goes after the = sign.
   5 − 2 = 3
4. Write the answer.
   5 − 2 = 3

Check. Add back to check: 3 + 2 = 5. ✓

Watch out. The sign is a minus, not a plus. Taking away makes the number smaller.

Key words. A missing number is shown by a box. Find the number that makes the sentence true.

Method. Start at 4. Count on until you reach 10. The number of counts is the missing number.

1. Start at 4, the number we know. Put your finger on it.
   Start: 4
2. Count on to 10. Say each number as you count on.
   5, 6, 7, 8, 9, 10
3. Count how many numbers you said. That many is the missing number.
   6 numbers
4. Write the missing number.
   6

Check. 4 + 6 = 10. ✓

Watch out. Count the numbers after 4, not 4 itself.

Key words. Adding undoes taking away.

Method. Undo the take away. Put back the number that was taken away.

1. Look at the answer, 4. The answer is what is left after taking away.
   Answer: 4
2. Add 3 back on. Adding undoes taking away.
   4 + 3 = 7
3. Write the missing number.
   7

Check. 7 − 3 = 4. ✓

Watch out. Do not take the number away again. Put it back on instead.

Key words. A fact family is a set of sentences that use the same three numbers.

Method. Use the same three numbers. Swap the parts for the second addition. Take each part away from the whole for the subtractions.

1. Find the whole and the two parts. The whole is the biggest number.
   Whole 7, parts 3 and 4
2. Write the two addition sentences. Swap the parts round for the second one.
   3 + 4 = 7 and 4 + 3 = 7
3. Write the two subtraction sentences. Take each part away from the whole.
   7 − 3 = 4 and 7 − 4 = 3
4. Write the whole family.
   3 + 4 = 7, 4 + 3 = 7, 7 − 3 = 4, 7 − 4 = 3

Check. Check: 3 + 4 = 7 and 7 − 4 = 3. ✓

Watch out. In a subtraction sentence the whole always comes first.

Key words. The = sign means the two sides are the same amount.

Method. Work out 4 + 3, then check it against the number that was said.

1. Work out 4 + 3. Start at the bigger number and count on.
   Start at 4, count on 3: 7
2. Compare with what was said. Is the total the same as the number in the sentence?
   7 and 6
3. Write the answer.
   No. 4 + 3 = 7.

Check. Count all the things: 4 + 3 = 7. ✓

Watch out. Work out the total first. Do not guess from the numbers you can see.

Key words. A story sum is a short problem told as a story.

Method. Read the story. Decide if we add or take away. Then write one number sentence.

1. Find the two numbers in the story. The numbers tell us how many.
   3 and 4
2. Decide: add or take away? Things joining together means add.
   Joining, so we add
3. Write the number sentence. The sentence shows the story.
   3 + 4 = 7
4. Write the answer. Say what the number is for.
   7 stickers

Check. Count 7 stickers in total. ✓

Watch out. Ask: are things joining together, or going away?

Key words. Take away means some things go away. The − sign shows it.

Method. Read the story. Decide if we add or take away. Then write one number sentence.

1. Find the two numbers in the story. Start with the number we had.
   9 and 4
2. Decide: add or take away? Things going away means take away.
   Going away, so we take away
3. Write the number sentence. The sentence shows the story.
   9 − 4 = 5
4. Write the answer. Say what the number is for.
   5 ducks

Check. Add back the 4 that went: 5 + 4 = 9. ✓

Watch out. Start with the number you had at the beginning, not the number that went away.