A man filled his car's 8 gallon gas tank. He took a trip and used 3/4 tank. How many gallons of gas were used?

Answer 1

What this question is asking is "how much is 3/4 of 8 gallons?".

How do we do that? Easy, we just multiply 3/4 x 8. The trick is knowing when a question asks how much "of" something, it's telling us to multiply. When you see "of", think "times".

So:

How much is 3/4 of 8?

Is asking:

How much is 3/4 x 8?

How do we multiply fractions? Easy, multiply the top & bottom (numerator & denominator) straight across.

First we need to make "8" a fraction so we can do that. What is a whole number as a fraction? That number over "1".

That makes our equation:

3 8 24

-- x -- = ----

4 1 4

What's 24 over 4? That's 24 divided by 4, which is 6.

That's it, our answer is 6 gallons!