Simplify $-5\times w$−5×w.
Simplify $\left(-c\right)\times2$(−c)×2.
Simplify the expression $\left(-9n\right)\times2$(−9n)×2.
Simplify $8\times\left(-4c\right)$8×(−4c).
Generalise the properties of operations with fractional numbers and integers.