幾道簡算題4計算下面各題：1．6.8×16.8＋19.3×3.22．139×137/138＋137×1/1383．4.4

題目：

幾道簡算題4
計算下面各題：
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

解答：

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