Question

Fill the blank:
$20\times 4\times 5=40\times 2\times$ _____

• A. 10
• B. 40
• C. 50
• D. 5

Answer 1

The correct option is D 5

Associative property is defined as:
When we multiply three or more numbers, regardless of how we group the numbers, the product remains the same.

It can be represented as:
$(a\times b)\times c=a\times (b\times c)$

So, the expression in the question can be written as:
$20\times 4\times 5=2\times 10\times 4\times 5$
$=2\times (10\times 4)\times 5$
$=2\times 40\times 5$
$=40\times 2\times 5$
$\text{(By commutative property)}$

So, the value in the blank is 5.