Question

SHOW STEPS PLEASE...

Answer 1

9514 1404 393

Answer:

  (5 15/20) -(2 8/20) = 3 7/20

Step-by-step explanation:

Problems in "least common denominator" are made much easier if you are familiar with your times tables.

When you compare the denominator 4 to the denominator 20, you see that ...

  20 = 5 × 4

An equivalent fraction is made by multiplying by 1. Here, the version of 1 you want for the top fractions is 5/5.

  $\dfrac{3}{4}= \dfrac{3}{4}\cdot\dfrac{5}{5}=\dfrac{3\cdot5}{4\cdot5}=\dfrac{15}{20}$

Similarly, the bottom fraction has its denominator multiplied by 4 to get from 5 to 20. The equivalent fraction is found by multiplying the numerator by the same number.

  $\dfrac{2}{5}=\dfrac{2\cdot4}{5\cdot4}=\dfrac{8}{20}$

Then the desired difference is ...

  $5\dfrac{15}{20}-2\dfrac{8}{20}=(5-2)+\left(\dfrac{15-8}{20}\right)=3\dfrac{7}{20}$