百分之四十九乘以九十八用简便计算怎么解
49% × 98 = 0.49 × 98 = (0.5 - 0.01) × (100 - 2)
= 0.5 *100 - 0.5 * 2 - 0.01 * 100 + 0.01 * 2
= 50 - 1 - 1 + 0.02
= 48.02
嗯,诀窍在于把数字尽量往“整”的化,比如0.49 -> 0.5 98 -> 100
= 0.5 *100 - 0.5 * 2 - 0.01 * 100 + 0.01 * 2
= 50 - 1 - 1 + 0.02
= 48.02
嗯,诀窍在于把数字尽量往“整”的化,比如0.49 -> 0.5 98 -> 100
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第1个回答 2017-06-08
0.8x0.25x0.4x12.5=(0.25x0.4)x(0.8x12.5)=0.1x10=1 0.8x0.25x0.4x12.5=(0.25x0.4)x(8x1.25)=0.1x10=1 望采纳!O(∩_∩)O~