要用简便算法:41.2×8.1+9 1/4+53.7×1.9 9 1/4=九又四分之一
问题描述:
要用简便算法:41.2×8.1+9 1/4+53.7×1.9 9 1/4=九又四分之一
1.9和9 1/4是分开的,9 1/4=九又四分之一是备注
答
41.2×8.1+9又 1/4+53.7×1.9
=41.2×8.1+9.25+(41.2+12.5)×1.9
=41.2×8.1+41.2×1.9+12.5×1.9+9.25
=41.2×(8.1+1.9)+1.25×19+1.25+8
=41.2×10+1.25×(19+1)+8
=412+8+1.25×20
=420+25
=445