用简便方法计算.4/5*4+2/5*2+1/5*16五分之四,五分之二和五分之一.

Question

用简便方法计算.
4/5*4+2/5*2+1/5*16
五分之四,五分之二和五分之一.

Answer 1

=4/5×4+4/5×1+4/5×4
=4/5×（4+1+4）
=4/5×9
=36/5
=7又5分之1