Question

Use mental math to find the missing factor 36,000 ÷ A 4 B 40 C 400 D 4000 = 90

Answer 1

To find the missing factor \( A \) in the equation \( 36,000 ÷ A = 90 \), we can rearrange the equation to solve for \( A \):

\[
A = \frac{36,000}{90}
\]

Now, we can simplify \( \frac{36,000}{90} \) using mental math:

1. First, simplify \( \frac{36,000}{90} \) by dividing both the numerator and denominator by 10:
\[
\frac{36,000 \div 10}{90 \div 10} = \frac{3,600}{9}
\]

2. Next, divide \( 3,600 \) by \( 9 \).
- \( 3,600 \div 9 \) can be simplified; first, we can calculate:
\[
3,600 = 3,590 + 10 = 3,600 - 9 = 3,590 - 2 = 599 - 1
\]
- However, we know \( 9 \) goes into \( 36 \) exactly \( 4 \) times with a remainder, so:

Therefore:
\[
600 ÷ 9 = 400
\]

Putting this together:

- \( 3,600 ÷ 9 = 400 \)

Thus, we find that \( A = 400 \).

The correct answer is \( C \) \( 400 \).