Question

What is the answer to 2/5 - 1/3?

Answer 1

Hi Student!

Looking at the problem statement and them just asking for us to determine the difference between two numbers seems like an easy task.  The first thing that we must do is to find a common denominator so we subtract them otherwise we can not since the denominators are different.

The denominators of the fractions are 5 and 3 and we know that they both multiply up to 15 so that can be our common denominator.

Convert to common denominator

• $\frac{2}{5}-\frac{1}{3}$

• $\frac{2*3}{5*3}-\frac{1*5}{3*5}$

• $\frac{2*3}{15}-\frac{1*5}{15}$

• $\frac{6}{15}-\frac{5}{15}$

Subtract

• $\frac{6}{15}-\frac{5}{15}$

• $\frac{6-5}{15}$

• $\frac{1}{15}$

Therefore, the final answer to the question asking the difference between 2/5 and 1/3 would be 1/15.

Answer 2

Answer:  1/15

Work Shown:

2/5 - 1/3

6/15 - 5/15

(6-5)/15

1/15

Here are two ways to check the answer:

• Type 2/5 - 1/3 into your calculator to get roughly 0.06667. The 6's actually repeat forever, but of course the calculator rounds at some point. You should notice that 1/15 has the same decimal value. Therefore 2/5 - 1/3 = 1/15
• Type (2/5-1/3) - (1/15) into your calculator. You should get zero or very close to it. I'm using the fact that if A = B, then A-B = 0.