question_answer 17)

Make up as many expressions with numbers (no variables) as you can from three numbers 5, 7 and 8. Every number should be used not more than once. Use only addition, subtraction and multiplication. (Hints Three possible expressions are \[5+(8-7),5-(8-7),(5\text{ }x\text{ }8)+7,\]make the other expressions.)

Answer:

                The possible expressions formed by three numbers 5, 7 and 8 are \[5+(8-7),5-(8-7),(5\times 8)+7,(5+8)+7,\] \[5-(8\times 7),(5+8)-7,(5\times 8)-7,8\times (7+5)\]etc.