3.2*1.8+2.54和198*0.51简便运算

3.2*1.8+2.54=3.2x(2-0.2)+2.54
=6.4-0.64+2.54
=6.4+1.9
=8.3
198*0.51=(200-2)x0.51
=102-1.02
=100.98

3.2×1.8+2.54
=(3+0.2)×1.8+2.54
=3×1.8+0.2×1.8+2.54
=5.4+0.36+2.54
=8.3
198×0.51
=(200-2)×0.51
=200×0.51-2×0.51
=102-1.02
=100.98

3.2*2-3.2*0.2+2.54
=6.4-0.64+1.9+0.64
=6.4+1.9
=8.3
198*0.51
=198*0.5+198*0.01
=99+1.98
=100.98