Question

Make up as many expressions with numbers (no variables) as you can from three numbers $5,7\mathrm{and}8.$ Every number should be used not more than once. Use only addition, subtraction and multiplication.

Answer 1

Make different expressions in addition, subtraction and multiplication.

Given: $5,7\mathrm{and}8.$ Each number can use only one time.

Different expressions are as follows:

$$\begin{gathered} \left(\mathrm{a}\right)(5+7)-8 \\ \left(\mathrm{b}\right)(7+8)\times 5 \\ \left(\mathrm{c}\right)(5\times 8)-7 \\ \left(\mathrm{d}\right)(5–8)\times 7 \\ \left(\mathrm{e}\right)(7–5)\times 8 \\ \left(\mathrm{f}\right)(5\times 7)+8 \end{gathered}$$

Hence these are the expressions formed by $5,7\mathrm{and}8.$