3.8*2.1+8.4*6.2+3.8*6.3简便运算下午考试

问题描述:

3.8*2.1+8.4*6.2+3.8*6.3简便运算
下午考试

3.8*2.1+8.4*6.2+3.8*6.3
=3.8*2.1+3.8*6.3+8.4*6.2
=3.8(2.1+6.3)+8.4*6.2
=3.8*8.4+8.4*6.2
=8.4*(3.8+6.2)
=8.4*10
=84

=3.8×(2.1+6.3)+8.4×6.2
=3.8×8.4+8.4×6.2
=8.4×(3.8+6.2)=
84