第22页

信息发布者:

$=(138 + 1)×\frac{137}{138} + 137×(1+\frac{1}{138})$
$=138×\frac{137}{138}+\frac{137}{138}+137+137×\frac{1}{138}$
$=137+\frac{137}{138}+137+\frac{137}{138}$
$=137×2+2×(1-\frac{1}{138})$
$=276-2×\frac{1}{138}$
$=275\frac{68}{69}$
$=(30+1\frac{1}{2})÷\frac{3}{2}+(40+1\frac{1}{3})÷\frac{4}{3}+(50+1\frac{1}{4})÷\frac{5}{4}$
$=30÷\frac{3}{2}+1\frac{1}{2}÷\frac{3}{2}+40÷\frac{4}{3}+1\frac{1}{3}÷\frac{4}{3}+50÷\frac{5}{4}+1\frac{1}{4}÷\frac{5}{4}$
$=20+1+30+1+40+1$
$=93$
$=76×\frac{1}{23}-76×\frac{1}{53}+23×\frac{1}{53}+23×\frac{1}{76}-53×\frac{1}{23}+53×\frac{1}{76}$
$=\frac{1}{23}×(76-53)-\frac{1}{53}×(76-23)+\frac{1}{76}×(23+53)$
$=\frac{1}{23}×23-\frac{1}{53}×53+\frac{1}{76}×76$
$=1-1+1$
$=1$