1) 23,4273×5+76,5727×5+6,346=
(23,4273+76,5727)×5+6,346=100*5+6,346=506,346
2) 45,3×0,5×2+0,25×5,7×4= 45,3×(0,5×2)+(0,25×4)*5,7=45,3+5,7=51
3)1,21+4.68-(121:100)-(54756:10000)=1,21-1,21+4,68-5,4756=-0,7956
4) 123,45×6,789-678,9×1,2345=1,2345*100*6,789-6,789*100*1,2345=0