Evaluate: -10+(-21\div2+1 \times (-1))

Expression: $-10+\left( -21\div2+1 \times \left( -1 \right) \right)$

Any expression multiplied by $1$ remains the same

$-10+\left( -21\div2+\left( -1 \right) \right)$

Divide the numbers

$-10+\left( -10.5+\left( -1 \right) \right)$

When there is a $+$ in front of an expression in parentheses, the expression remains the same

$-10+\left( -10.5-1 \right)$

Calculate the difference

$-10+\left( -11.5 \right)$

When there is a $+$ in front of an expression in parentheses, the expression remains the same

$-10-11.5$

Calculate the difference

$\begin{align*}&-21.5 \\&\begin{array} { l }-\frac{ 43 }{ 2 },& -21 \frac{ 1 }{ 2 }\end{array}\end{align*}$