1. **State the problem:** We need to perform the following arithmetic operations: 1) $99169 + 21983$ 2) $17810 + 48765$ 3) $86854 + 38213$ 4) $61978 - 43916$ 5) $55087 - 24292$ 2. **Addition and subtraction rules:** - Addition combines two numbers into a larger number. - Subtraction finds the difference between two numbers. 3. **Calculate each operation step-by-step:** 1) $99169 + 21983$ $$\begin{aligned} 99169 + 21983 &= 99169 + 20000 + 1983 \\ &= 119169 + 1983 \\ &= 121152 \end{aligned}$$ 2) $17810 + 48765$ $$\begin{aligned} 17810 + 48765 &= 17810 + 40000 + 8765 \\ &= 57810 + 8765 \\ &= 66575 \end{aligned}$$ 3) $86854 + 38213$ $$\begin{aligned} 86854 + 38213 &= 86854 + 30000 + 8213 \\ &= 116854 + 8213 \\ &= 125067 \end{aligned}$$ 4) $61978 - 43916$ $$\begin{aligned} 61978 - 43916 &= 61978 - 40000 - 3916 \\ &= 21978 - 3916 \\ &= 18062 \end{aligned}$$ 5) $55087 - 24292$ $$\begin{aligned} 55087 - 24292 &= 55087 - 20000 - 4292 \\ &= 35087 - 4292 \\ &= 30795 \end{aligned}$$ 4. **Final answers:** 1) $121152$ 2) $66575$ 3) $125067$ 4) $18062$ 5) $30795$