Question

五分之二乘十分之二加十分之九乘零点四减2除5乘十分之一 !按运算顺序算,和简便方法算,两种都要

Answer 1

按运算顺序

2/5x2/10+9/10x0.4-2÷5x1/10

=2/5x2/10+9/10x2/5-2/5x1/10

=2/25+9/25-1/25

=10/25

=2/5

简便算法

2/5x2/10+9/10x0.4-2÷5x1/10

=2/5x2/10+9/10x2/5-2/5x1/10

=2/5x(2/10+9/10-1/10)

=2/5x1

=2/5