Answer
$\frac{4}{3}$
Work Step by Step
[7+3(2$^3$-1)]$\div$21
First solve the exponent inside the parentheses
[7+3(8-1)]$\div$21
Then subtract inside the parentheses
[7+3(7)]$\div$21
Then multiply inside the brackets
[7+21]$\div$21
Then add inside the brackets
[28]$\div$21
Then divide
$\frac{28}{21}$
Then reduce by 7
$\frac{4}{3}$
