$90-3\left( {3}^{3}-3 \times {2}^{3} \right)+6$
Evaluate the power$90-3\left( 27-3 \times {2}^{3} \right)+6$
Evaluate the power$90-3\left( 27-3 \times 8 \right)+6$
Multiply the numbers$90-3\left( 27-24 \right)+6$
Subtract the numbers$90-3 \times 3+6$
Multiply the numbers$90-9+6$
Calculate the sum or difference$87$