Simplify the expression $\frac{-7x}{7}$−7x7.

Simplify the expression $\frac{-14a}{2}$−14a2.

Convert the expression $\left(-8m\right)\div64$(−8m)÷64 to a fraction and simplify.

Simplify the expression $\frac{-4m^2}{32}$−4m232.