Question

43×141-43×40+43，用简便方法怎么算？

Answer 1

(1 / 37 + 1 / 41 + 1 / 43 + 1 / 47 + 1 / 53) * (1 / 41 + 1 / 43 + 1 / 47 + 1 / 53 + 1 / 54) - (1 / 37 + 1 / 41 + 1 / 43 + 1 / 47 + 1 / 53 + 1 / 54) * (1 / 41 + connected: 1 / 43 + 1 / 47 + 1 / 53) = (1 / 37 + 1 / 41 + 1 / 43 + 1 / 47 + 1 / 53) * (1 / 41 + 1 / 43 + 1 / 47 + 1 / 53) + (1 / 37 + 1 / 41 + 1 / 43 + 1 / 47 + 1 / 53) * (1 /54) - (1 / 37 + 1 / 41 + 1 / 43 + 1 / 47 + 1 / 53) * (1 / 41 + 1 / 43 + 1 / 47 + 1 / 53) - (1 / 54) * (1 / 41 + 1 / 43 + 1 / 47 + 1 / 53) = (1 / 37 + 1 / 41 + 1 / 43 + 1 / 47 + 1 / 53) * (1 / 54) - (1 / 54) * (1 / 41 + 1 / 43 + 1 / 47 + 1 / 53) = (1 / 54) * (1 / 37) = 1 / 1998

Answer 2

=（1/37+1/41+1/43+1/47+1/53）*(1/41+1/43+1/47+1/53)+(1/37+1/41+1/43+1/47+1/53)*(1/54)-(1/37+1/41+1/43+1/47+1/53)*(1/41+1/43+1/47+1/53)-(1/54)*(1/41+1/43+1/47+1/53)
=(1/37+1/41+1/43+1/47+1/53)*(1/54)-(1/54)*(1/41+1/43+1/47+1/53)
=(1/54)*(1/37)
=1/1998

Answer 3

43×141-43×40+43
=43×（141-40+1）
=43×（100+2）
=43×100+43×2
=4300+43
=4343

Answer 4

=（1/37+1/41+1/43+1/47+1/53）*(1/41+1/43+1/47+1/53)+(1/37+1/41+1/43+1/47+1/53)*(1/54)-(1/37+1/41+1/43+1/47+1/53)*(1/41+1/43+1/47+1/53)-(1/54)*(1/41+1/43+1/47+1/53)
=(1/37+1/41+1/43+1/47+1/53)*(1/54)-(1/54)*(1/41+1/43+1/47+1/53)
=(1/54)*(1/37)
=1/1998