Question

-1/5 + 3/4

Answer 1

First find a common denominator.

Answer 2

What is the lowest common denominator?

Answer 3

3/4

Answer 4

in decimal form it would be 0.55.

Answer 5

^^hes right

Answer 6

or 11/20 (?)

Answer 7

11/20

Answer 8

Here is how we find the lowest common denominator...

\(\sf \color{black}{Multiples ~of ~5 ~= ~5, ~10,~ 15, ~}\color{magenta}{20}\)

\(\sf \color{black}{Multiples ~of ~4 ~= ~4, ~8,~ 12,~ 16, ~}\color{magenta}{20}\)

So the lowest common denominator is \(\sf \color{magenta}{20}\)

Answer 9

Now since we have found our denominator, we have to find our new numerators for our fractions...

All we have to do is plug each fraction given, \(\sf \frac{-1}{5}\) and \(\sf \frac{3}{4}\), into the formula below

\(\sf \color{magenta}{(20/denominator)}~x~Numerator~=~New~Numerator\)

Answer 10

\(\sf \LARGE \frac{\color{blue}{-1}}{\color{yellow}{5}}\)

\(\sf \color{magena}{(20/\color{yellow}{5})}~x~\color{blue}{-1}~=~New~Numerator\)

\(\sf \LARGE \frac{\color{blue}{3}}{\color{yellow}{4}}\)

\(\sf \color{magena}{(20/\color{yellow}{4})}~x~\color{blue}{3}~=~New~Numerator\)

Answer 11

\(\sf \color{magena}{(20/\color{yellow}{5})}~x~\color{blue}{-1}~=~-4\)

and

\(\sf \color{magena}{(20/\color{yellow}{4})}~x~\color{blue}{3}~=~15\)

SO our new fraction for \(\sf \large \frac{-1}{5}\) is \(\sf \large \frac{-4}{20}\) and our new fraction for \(\sf \large \frac{3}{4}\) is \(\sf \large \frac{15}{20}\)

Answer 12

So now we plug in \(\sf \large \frac{-4}{20}\) and \(\sf \large \frac{15}{20}\) where \(\sf \large \frac{-1}{5}\) and \(\sf \large \frac{3}{4}\) was in the original problem


\(\sf \large \frac{-1}{5}\) + \(\sf \large \frac{3}{4}\)

\(\sf \large \frac{-4}{20}\) + \(\sf \large \frac{15}{20}\)