=4.4×57.8+(57.8-12.5)×5.6
=4.4×57.8+5.6×57.8-12.5×5.6
=(4.4+5.6)×57.8-12.5×0.8×7
=10×57.8-10×7
=578-70
=508
4.4×57.8+45.3×5.6 用简便运算
=4.4×57.8+(57.8-12.5)×5.6
=4.4×57.8+5.6×57.8-12.5×5.6
=(4.4+5.6)×57.8-12.5×0.8×7
=10×57.8-10×7
=578-70
=508