Solve 21/2*81/2-12

$$21 / 2 \times 81 / 2 - 12$$

Evaluate

$$\frac{1653}{4}=413.25$$

Solution Steps

Multiply \frac{21}{2} times \frac{81}{2} by multiplying numerator times numerator and denominator times denominator.

$$\frac{21\times 81}{2\times 2}-12$$

Do the multiplications in the fraction \frac{21\times 81}{2\times 2}.

$$\frac{1701}{4}-12$$

Convert 12 to fraction \frac{48}{4}.

$$\frac{1701}{4}-\frac{48}{4}$$

Since \frac{1701}{4} and \frac{48}{4} have the same denominator, subtract them by subtracting their numerators.

$$\frac{1701-48}{4}$$

Subtract 48 from 1701 to get 1653.

$$\frac{1653}{4}$$

Factor

$$\frac{3 \cdot 19 \cdot 29}{2 ^ {2}} = 413\frac{1}{4} = 413.25$$