Solve 21/4-22/5

$$2 \frac { 1 } { 4 } - 2 \frac { 2 } { 5 }$$

Evaluate

$$-\frac{3}{20}=-0.15$$

Solution Steps

Multiply 2 and 4 to get 8.

$$\frac{8+1}{4}-\frac{2\times 5+2}{5}$$

Add 8 and 1 to get 9.

$$\frac{9}{4}-\frac{2\times 5+2}{5}$$

Multiply 2 and 5 to get 10.

$$\frac{9}{4}-\frac{10+2}{5}$$

Add 10 and 2 to get 12.

$$\frac{9}{4}-\frac{12}{5}$$

Least common multiple of 4 and 5 is 20. Convert \frac{9}{4} and \frac{12}{5} to fractions with denominator 20.

$$\frac{45}{20}-\frac{48}{20}$$

Since \frac{45}{20} and \frac{48}{20} have the same denominator, subtract them by subtracting their numerators.

$$\frac{45-48}{20}$$

Subtract 48 from 45 to get -3.

$$-\frac{3}{20}$$

Factor

$$-\frac{3}{20} = -0.15$$