A student wants to solve 8 + 6 using the making-10 strategy. Which decomposition is correct?
ASplit the 8 into 4 + 4, then add 4 + 6 = 10, then add 4 more
BSplit the 6 into 2 + 4, then add 8 + 2 = 10, then add 4 more to get 14
CAdd 8 + 6 directly by counting up from 8 six times
DSplit both numbers in half: 4 + 3 = 7, then double it
The making-10 strategy asks: what does 8 need to reach 10? It needs 2. So you take 2 from the 6, leaving 4. Now 8 + 2 = 10, and 10 + 4 = 14. Option A splits the wrong addend — you want to fill the addend closest to 10, not split it. Option C works but misses the efficiency of using 10 as a bridge.
Question 2 Multiple Choice
Why is 10 a special 'bridge' number in the making-10 strategy?
ABecause 10 is the largest number students know at this stage
BBecause adding any number to 10 is easy — you just write the digit after 10
CBecause 10 is always the middle of any addition problem
DBecause 10 is even, making it easier to split
Our number system is built in groups of ten, so 10 + any single digit is immediately readable as a teen number (10 + 3 = 13, 10 + 7 = 17). This makes 10 an ideal stepping stone — once you hit 10, the remaining addition is trivial. This is not true of most other numbers, which is exactly why making-10 is worth learning as a specific strategy.
Question 3 True / False
To use the making-10 strategy for 9 + 5, you split the 5 into 1 and 4, add 9 + 1 = 10, then add 10 + 4 = 14.
TTrue
FFalse
Answer: True
This is exactly right. 9 needs only 1 more to reach 10, so you take 1 from the 5 (splitting it into 1 + 4), complete the 10, then add the remaining 4. The answer 14 is correct and the decomposition is valid. This strategy relies on knowing your number bonds — specifically that 5 = 1 + 4.
Question 4 True / False
The making-10 strategy works best when both addends are already close to each other in value.
TTrue
FFalse
Answer: False
The making-10 strategy works best when one addend is close to 10 (like 8 or 9), because you only need to borrow a small piece from the other addend to complete the ten. How close the two addends are to each other is not the relevant factor. For example, 9 + 2 works perfectly (borrow 1 from the 2, get 10 + 1 = 11), even though 9 and 2 are far apart.
Question 5 Short Answer
Why does passing through 10 make addition easier, rather than just adding the two numbers directly?
Think about your answer, then reveal below.
Model answer: Because adding any number to 10 is simple in our base-10 system — you just extend to a teen number. By decomposing one addend to fill up to 10 first, you replace a harder addition with two easy ones: filling to 10, then adding what's left.
The making-10 strategy works because it leverages the structure of our number system. Ten is a natural resting point where arithmetic becomes trivial. The cost is one decomposition step, but the benefit is that both remaining additions (getting to 10, then adding the rest) are much simpler. This also builds number sense — it teaches students that numbers can be broken apart and recombined without changing their total.