7.2×16又3/10+73.8×2又4/5 12.5×1.86+42÷1又2/5+25.4×1又1/41/4×7又5/7+0.25×3又2/7+1/4

7.2×16又3/10+73.8×2又4/5 12.5×1.86+42÷1又2/5+25.4×1又1/41/4×7又5/7+0.25×3又2/7+1/4
7.2×16又3/10+73.8×2又4/5
12.5×1.86+42÷1又2/5+25.4×1又1/4
1/4×7又5/7+0.25×3又2/7+1/4

7.2×16又3/10+73.8×2又4/5 12.5×1.86+42÷1又2/5+25.4×1又1/41/4×7又5/7+0.25×3又2/7+1/4
7.2×16又3/10+73.8×2又4/5
=7.2×16.3+73.8×2.8
=117.36+206.64
=324


12.5×1.86+42÷1又2/5+25.4×1又1/4
=12.5×1.86+42÷1.4+25.4×1.25
=1.25×18.6+25.4×1.25+42÷1.4
=1.25×(18.6+25.4)+30
=1.25×44+30
=1.25×(40+4)+30
=50+5+30
=85


1/4×7又5/7+0.25×3又2/7+1/4
=1/4×7又5/7+1/4×3又2/7+1/4×1
=1/4×(7又5/7+3又2/7+1)
=1/4×12
=3


利用的是简便算法,

7.2×16又3/10+73.8×2又4/5
=7.2×163/10+73.8×14/5
= 117.36+206.64
=324
12.5×1.86+42÷1又2/5+25.4×1又1/4
=12.5×1.86+42÷7/5+25.4×5/4
=23.25+30+31.75
=85
1/4×7又5/7+0.25×3又2/7+1/4
=1/4×54/7+0.25×23/7+1/4
=54/28+23/28+7/28
=84/28
=3