1-0.07=
0.5+2.05=
4.06× 1000=
10×0.01=
20×0.5=
1.2×0.3=
0.3×0.3=
19.8×4.2≈
①2+8×1.25
②17.8×5.6+12.2×5.6
③3.7×99
④2.5×0.32×1.25
元,应缴纳电费约多少元?( 得数保留两位小数)