简便计算
74×57 +42×74+74
=74x(57+42+1)
=74x100
=7400
74×57+42×74÷74
=74×57+42×(74÷74)
=(70+4)×57+42×1
=70×57+4×57+42
=70×(50+7)+4×(50+7)+42
=70×50+70×7+4×50+4×7+42
=3500+490+200+28+42
=4260
74*57+42*74/74
=74*57+42*(74/74)
=74*57+42
=74*50+74*7+6*7
=74*50+7*(74+6)
=3700+7*80
=4260