Using the any-order property of multiplication
The any-order property of multiplication can be used to simplify calculations by changing the order in which we perform multiplications.
For example:
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= (2 × 5) × (2 × 5) × (2 × 5) |
= 10 × 10 × 10 | |
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Sometimes this reordering happens after we decompose one of the factors, such as when we double twice in order to multiply by four, as in
17 × 4 = (17 × 2) × 2 = 34 × 2 = 68
This technique of moving a factor from one number to another in order to simplify a calculation has applications beyond repeated doubling, as in
36 × 5 = 18 × (2 × 5) = 180.