Step 1 is justified by the commutative property of multiplication. Swapping the order of the factors, 12 and 10, does not change the value of the expression. Step 2 is justified by the associative property of multiplication. Moving the parentheses to multiply 3 by 12 first, rather than multiplying 12 and 10 first, does not change the value of the expression. Step 3 is justified by the order of operations. Expressions in parentheses are resolved first. Step 4 is multiplication. The value of the expression is 360.
Work Step by Step
The commutative property says that the order of the factors does not change the product. The associative property says that the way factors are grouped does not change the product.