3(15-6)
=45-18
=27
5×3×2+7×7
=30+49
=79
172-4×8×5
=172-160
=12
80/5×4
=80/20
=4
36- (24/4)
=36-6
=30
2×5²
=2×25
=50
60-5×3²+6²
=60-5×9+36
=60-45+36
=15+36
=51
