Question

What is (3×10) ×8= ------ × (10×8) elementary 5th grade

Answer 1

Using the property $(a\times b) \times c = a \times (b\times c)$, we know that 3 is the missing number.

Answer 2

This is an example of the commutative property of multiplication.

That property states: $(a \times b) \times c = a \times (b \times c)$

So using that property, we can figure out that 3 should be in the blank.