When adding and multiplying you may swap the numbers, the answer stays the same!
Example: 12 × 250 = 3,000 and 250 × 12 = 3,000
Example: 2,450 + 3,125 = 5,575 and 3,125 + 2,450 = 5,575
This helps with smart calculating. You can pick the version that feels easier.
The numbers filled in show the solution.
Examples
Example: Swap Fact when Multiplying
12×250=3000↔250×12=3000
Example: Swap Fact when Adding
2450+3125=5575↔3125+2450=5575
For parents
What does this exercise practice?
Using the commutative law for adding and multiplying, also with big numbers, to pick the easier calculation.
Common pitfalls
Swapping does not work for subtracting and dividing. 9 − 3 is not the same as 3 − 9.
How to practice at home
Swap the order of the amounts on a shopping bill and check that the same total comes out.
Related: Inverse problems, Key facts, Times before plus