Question

42x28十71x47十47用简便方法计算该怎样做

42x28十71x47十47用简便方法计算该怎样做

Answer 1

42x28十71x47十47
=42*28+72*47
=42*（28+72）+72*5
=4200+360
=4560

Answer 2

42×28+72×47
=6×7×4×7+72×47
=24×7×7+24×3×47
=24×(49+141)
=24×190
=4560

Answer 3

42×28+71×47+47
=42×28+47×（71+1）
=42×28+47×72
=42×28+42×72+5×72
=42×（28+72）+360
=42×100+360
=4200+360
=4560

Answer 4

最简便方法：手机计算器一输入就OK，简单吧？