Evaluate: -2.1+2.4

Expression: $-2.1+2.4$

Keep the sign of the number with the larger absolute value and subtract the smaller absolute value from the larger

$+\left( 2.4-2.1 \right)$

Subtract the numbers

$\begin{align*}&0.3 \\&\begin{array} { l }\frac{ 3 }{ 10 },& 3 \times {10}^{-1}\end{array}\end{align*}$