Multiply with the Distributive Property
Split one factor into parts you know, multiply each part, then add the products.
Seven groups of 8 are five groups of 8 plus two groups of 8. The groups do not change size. You only split how many groups there are. That is why 7 × 8 = 5 × 8 + 2 × 8. Use parts that already have a fact: 5s, 2s, and 10s are the useful ones.
7 × 8. Split 7 into 5 and 2. 5 × 8 = 40. 2 × 8 = 16. The two products are parts of the same total, so add them: 40 + 16 = 56. 7 × 8 = 56.
5 × 8 = 40
Use the 5s fact.
2 × 8 = 16
Use the double.
40 + 16 = 56
Add the two products.
- Split one factor into parts you can already multiply.
- Multiply each part by the other factor.
- Add those products.
- Do not add the parts to the other factor.
6 × 7 can split 6 into 5 and 1. 5 × 7 = 35, 1 × 7 = 7, and 35 + 7 = 42. 8 × 6 can split 8 into 5 and 3. 5 × 6 = 30, 3 × 6 = 18, and 30 + 18 = 48. Or split 6 into 5 and 1 if the 5s feel easier.
Watch out
- Adding 5 and 2 onto 8 instead of multiplying each part by 8.
- Forgetting to add the two products.
- Splitting into parts you still cannot multiply.
What is 6 × 7 this way?
6 is 5 + 1. 5 × 7 = 35, 1 × 7 = 7, and 35 + 7 = 42.
What is 8 × 6?
Split 8 into 5 and 3. 5 × 6 = 30, 3 × 6 = 18, and 30 + 18 = 48.
Math practice for Distributive Property
Multiplication
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