几道简算题4计算下面各题:1.6.8×16.8+19.3×3.22.139×137/138+137×1/1383.4.4×57.8+45.3×5.6

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几道简算题4计算下面各题:1.6.8×16.8+19.3×3.22.139×137/138+137×1/1383.4.4×57.8+45.3×5.6几道简算题4计算下面各题:1.6.8×16.8+19

几道简算题4计算下面各题:1.6.8×16.8+19.3×3.22.139×137/138+137×1/1383.4.4×57.8+45.3×5.6
几道简算题4
计算下面各题:
1.6.8×16.8+19.3×3.2
2.139×137/138+137×1/138
3.4.4×57.8+45.3×5.6

几道简算题4计算下面各题:1.6.8×16.8+19.3×3.22.139×137/138+137×1/1383.4.4×57.8+45.3×5.6
1.6.8×16.8+19.3×3.2
=6.8×16.8+(16.8+2.5)×3.2
=6.8×16.8+16.8×3.2+2.5×3.2
=16.8×(6.8+3.2)+2.5×4×0.8
=16.8×10+10×0.8
=168+8
=176
2.139×137/138+137×1/138
=139×(1-1/138)+137/138
=139×1-139/138+137/138
=139-2/138
=138又68/69
3.4.4×57.8+45.3×5.6
=4.4×(45.3+12.5)+45.3×5.6
=4.4×45.3+4.4×12.5+45.3×5.6
=45.3×(4.4+5.6)+4×12.5×1.1
=45.3×10+50×1.1
=453+55
=508