奥数题简便方法用简便方法计算

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奥数题简便方法用简便方法计算
奥数题简便方法
用简便方法计算

奥数题简便方法用简便方法计算
2.解原式=67×1/4+75/2×1/4-9/2×1/4
=1/4×(67+75/2-9/2)
=1/4×100
=25
3.原式=7.6×3.6+0.36×50-36×0.26
=7.6×3.6+3.6×5+3.6×2.6
=3.6×(7.6+5-2.6)
=3.6×10
=36
4.原式=0.1111×8×0.6+0.1111×2×7.6
=0.1111×(4.8+15.2)
=0.1111×20
=2.222
5.原式=5.6×10.2-1.4×4×0.2
=5.6×(10.2-0.2)
=5.6×10
=56
7.原式=465×8.2+465×29.6-(465-100)×37.8
=465×8.2+465×29.6-465×37.8+100×37.8
=465×(8.2+29.6-37.8)+100×37.8
=465×0+100×37.8
= 3780
8.原式=1/4×17×166-1/4×170×14.2+1/4×24×23
=1/4×(17×166-17×142+24×23)
=1/4×[17×(166-142)+24×23]
=1/4×[17×24+24×23]
=1/4×24×(17+23)
=1/4×24×40
=240