Question

31.3×8.1+12.5×6.1+4.38×1.9怎样简便计算？

Answer 1

要简便计算表达式 31.3×8.1+12.5×6.1+4.38×1.9，我们可以按照以下步骤进行：

• 观察数字的特点，尽量使用整数计算。可以将小数点右移一位，将小数转换为整数。

  31.3×8.1+12.5×6.1+4.38×1.9
  = (313×81 + 125×61 + 438×19) ÷ 10

• 计算整数部分的乘积：
  313×81 = 25,353
  125×61 = 7,625
  438×19 = 8,322

• 将三个整数的和除以10，得到最终结果：
  (25,353 + 7,625 + 8,322) ÷ 10
  = 41,300 ÷ 10
  = 4,130

因此，简便计算后的结果为 4,130。

Answer 2

31.3×8.1+12.5×6.1+4.38×1.9
=31.3×(10-1.9)+12.5×(8-1.9)+4.38×1.9
=313-31.3×1.9+100-12.5×1.9+4.38×1.9
=(313+100)+1.9×(-31.3-12.5+4.38)
=413+1.9×(-43.8+4.38)
=413+1.9×4.38×(-10+1)
=413+1.9×4.38×(-9)
=413-74.898
=338.102

Answer 3

简便计算：
31.3×8.1+12.5×6.1+4.38×1.9
=31.3×(10-1.9)+12.5×(8-1.9)+4.38×1.9
=313-31.3×1.9+100-12.5×1.9+4.38×1.9
=413-1.9×(31.3+12.5-4.38)
=413-1.9×39.42
=413-(2-0.1)×39.42
=413-78.84+3.942
=338.102