Step-by-step Maths Level 2: Making 10 first
Part of the Step-by-step Maths Level 2 adding within 20 chapter. Chapter overview · whole chapter on one page
Making 10 first
Some sums go past 10. To make them easier, make 10 first.
Split the second number so that the first number reaches 10. Then add what is left.
Key ideas
- Make 10 first, then add the rest.
- Use bonds to 10 to find how many make 10.
- Adding to 10 is easy.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 8 needs to make 10. 8 needs 2 more to make 10.10 - 8 = 2
- Split 5 into 2 and 3. Use 2 to make 10. Then add 3.5 = 2 + 3
- Add the rest to 10. 8 + 2 = 10, and 10 + 3 = 13.10 + 3 = 13
- Write the answer. 13
Check. Count on: 8 + 5 = 13.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 7 needs to make 10. 7 needs 3 more to make 10.10 - 7 = 3
- Split 6 into 3 and 3. Use 3 to make 10. Then add 3.6 = 3 + 3
- Add the rest to 10. 7 + 3 = 10, and 10 + 3 = 13.10 + 3 = 13
- Write the answer. 13
Check. Count on: 7 + 6 = 13.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 9 needs to make 10. 9 needs 1 more to make 10.10 - 9 = 1
- Split 4 into 1 and 3. Use 1 to make 10. Then add 3.4 = 1 + 3
- Add the rest to 10. 9 + 1 = 10, and 10 + 3 = 13.10 + 3 = 13
- Write the answer. 13
Check. Count on: 9 + 4 = 13.
Watch out. Making 10 first is easier because 10 is simple to add to.
Watch out
Watch out. When you split the second number, use the right part to make 10. 8 needs 2, not 5.
Exam tip
Grown-up tip. Use a ten frame. Fill it up to ten, then count the counters left over.
Exercise 5B Practice: making 10 first
Non-calculatorMethod. Use the number that makes 10 with the first number. Then add what is left.
- Find what 8 needs to make 10. 8 needs 2 more to make 10.10 - 8 = 2
- Split 5 into 2 and 3. Use 2 to make 10. Then add 3.5 = 2 + 3
- Add the rest to 10. 8 + 2 = 10, and 10 + 3 = 13.10 + 3 = 13
- Write the answer. 13
Check. Count on: 8 + 5 = 13.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 4 needs to make 10. 4 needs 6 more to make 10.10 - 4 = 6
- Split 8 into 6 and 2. Use 6 to make 10. Then add 2.8 = 6 + 2
- Add the rest to 10. 4 + 6 = 10, and 10 + 2 = 12.10 + 2 = 12
- Write the answer. 12
Check. Count on: 4 + 8 = 12.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 5 needs to make 10. 5 needs 5 more to make 10.10 - 5 = 5
- Split 7 into 5 and 2. Use 5 to make 10. Then add 2.7 = 5 + 2
- Add the rest to 10. 5 + 5 = 10, and 10 + 2 = 12.10 + 2 = 12
- Write the answer. 12
Check. Count on: 5 + 7 = 12.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 8 needs to make 10. 8 needs 2 more to make 10.10 - 8 = 2
- Split 6 into 2 and 4. Use 2 to make 10. Then add 4.6 = 2 + 4
- Add the rest to 10. 8 + 2 = 10, and 10 + 4 = 14.10 + 4 = 14
- Write the answer. 14
Check. Count on: 8 + 6 = 14.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 6 needs to make 10. 6 needs 4 more to make 10.10 - 6 = 4
- Split 9 into 4 and 5. Use 4 to make 10. Then add 5.9 = 4 + 5
- Add the rest to 10. 6 + 4 = 10, and 10 + 5 = 15.10 + 5 = 15
- Write the answer. 15
Check. Count on: 6 + 9 = 15.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 8 needs to make 10. 8 needs 2 more to make 10.10 - 8 = 2
- Split 4 into 2 and 2. Use 2 to make 10. Then add 2.4 = 2 + 2
- Add the rest to 10. 8 + 2 = 10, and 10 + 2 = 12.10 + 2 = 12
- Write the answer. 12
Check. Count on: 8 + 4 = 12.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 9 needs to make 10. 9 needs 1 more to make 10.10 - 9 = 1
- Split 4 into 1 and 3. Use 1 to make 10. Then add 3.4 = 1 + 3
- Add the rest to 10. 9 + 1 = 10, and 10 + 3 = 13.10 + 3 = 13
- Write the answer. 13
Check. Count on: 9 + 4 = 13.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 8 needs to make 10. 8 needs 2 more to make 10.10 - 8 = 2
- Split 7 into 2 and 5. Use 2 to make 10. Then add 5.7 = 2 + 5
- Add the rest to 10. 8 + 2 = 10, and 10 + 5 = 15.10 + 5 = 15
- Write the answer. 15
Check. Count on: 8 + 7 = 15.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 9 needs to make 10. 9 needs 1 more to make 10.10 - 9 = 1
- Split 6 into 1 and 5. Use 1 to make 10. Then add 5.6 = 1 + 5
- Add the rest to 10. 9 + 1 = 10, and 10 + 5 = 15.10 + 5 = 15
- Write the answer. 15
Check. Count on: 9 + 6 = 15.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 7 needs to make 10. 7 needs 3 more to make 10.10 - 7 = 3
- Split 7 into 3 and 4. Use 3 to make 10. Then add 4.7 = 3 + 4
- Add the rest to 10. 7 + 3 = 10, and 10 + 4 = 14.10 + 4 = 14
- Write the answer. 14
Check. Count on: 7 + 7 = 14.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 9 needs to make 10. 9 needs 1 more to make 10.10 - 9 = 1
- Split 8 into 1 and 7. Use 1 to make 10. Then add 7.8 = 1 + 7
- Add the rest to 10. 9 + 1 = 10, and 10 + 7 = 17.10 + 7 = 17
- Write the answer. 17
Check. Count on: 9 + 8 = 17.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 8 needs to make 10. 8 needs 2 more to make 10.10 - 8 = 2
- Split 8 into 2 and 6. Use 2 to make 10. Then add 6.8 = 2 + 6
- Add the rest to 10. 8 + 2 = 10, and 10 + 6 = 16.10 + 6 = 16
- Write the answer. 16
Check. Count on: 8 + 8 = 16.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 4 needs to make 10. 4 needs 6 more to make 10.10 - 4 = 6
- Split 9 into 6 and 3. Use 6 to make 10. Then add 3.9 = 6 + 3
- Add the rest to 10. 4 + 6 = 10, and 10 + 3 = 13.10 + 3 = 13
- Write the answer. 13
Check. Count on: 4 + 9 = 13.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 6 needs to make 10. 6 needs 4 more to make 10.10 - 6 = 4
- Split 8 into 4 and 4. Use 4 to make 10. Then add 4.8 = 4 + 4
- Add the rest to 10. 6 + 4 = 10, and 10 + 4 = 14.10 + 4 = 14
- Write the answer. 14
Check. Count on: 6 + 8 = 14.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 7 needs to make 10. 7 needs 3 more to make 10.10 - 7 = 3
- Split 6 into 3 and 3. Use 3 to make 10. Then add 3.6 = 3 + 3
- Add the rest to 10. 7 + 3 = 10, and 10 + 3 = 13.10 + 3 = 13
- Write the answer. 13
Check. Count on: 7 + 6 = 13.
Watch out. Making 10 first is easier because 10 is simple to add to.
Method. Use the number that makes 10 with the first number. Then add what is left.
- Find what 4 needs to make 10. 4 needs 6 more to make 10.10 - 4 = 6
- Split 7 into 6 and 1. Use 6 to make 10. Then add 1.7 = 6 + 1
- Add the rest to 10. 4 + 6 = 10, and 10 + 1 = 11.10 + 1 = 11
- Write the answer. 11
Check. Count on: 4 + 7 = 11.
Watch out. Making 10 first is easier because 10 is simple to add to.