18/17×4/5-4/17×3/5
=4/17×﹙8/5-3/5﹚
=4/17
2.2×125%+7.8÷80%
= 2.2×1.25+7.8×1.25
=1.25×﹙2.2+7.8﹚
=1.25×10
=12.5
17×14×﹙8/7-14/17﹚
=17×14×8/7-17×14×14/17
=17×16-14×14
=272-196
=76.
18/17×4/5-4/17×3/5
=4/17×﹙8/5-3/5﹚
=4/17
2.2×125%+7.8÷80%
= 2.2×1.25+7.8×1.25
=1.25×﹙2.2+7.8﹚
=1.25×10
=12.5
17×14×﹙8/7-14/17﹚
=17×14×8/7-17×14×14/17
=17×16-14×14
=272-196
=76.