Checking and further securing understanding of the commutative law

12 questions

1. Using the Gattegno chart or otherwise, work out which of the following calculations equate to 48.
2. Using the Gattegno chart or otherwise, match each calculation to its correct answer.
3. Using the associative law to partition 5000 and 7000 into powers of 10, find the calculations that are equivalent to 7000 × 5000.
4. Which of the following calculations are equivalent to 3000\times2000?
5. Without using a calculator, work out 0.007 × 30.
6. Which of the following calculations are equivalent to 4.5\times0.05?
7. A ___ number is an integer greater than one with exactly two factors.
8. Which of the following products only use prime numbers?
9. Write 200 as a product of its prime factors.
10. Use the fact that 60 = 2² × 3 × 5 to write 180 as a product of its prime factors.
11. Use the fact that 60 = 2² × 3 × 5 to write 20 as a product of its prime factors.
12. 165 = 3 × 5 × 11 and 42 = 2 × 3 × 7. Which of the following is the most useful arrangement to calculate 165 × 42?

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