bonjour,
0.21:3 (0.21*100=21 21:3=7 7:100=0.07
4.3:5 4.3*100=430 430:5=86 86/100=0.86
92:100 92 centièmes 0.92
0.75x4 0.75=3/4 3/4x4=3
20-12.1 20x10=200 12.1x10=121 200-121=79 79:10=7.9
138:6 138=120+18 120:6=20 18:6=3 ( 120+18):6=(20+3) 138:6=23
273.04+115.7 273+115=388 0.04-0.7= 0.74 388/74
100x7.6 7.6 centaines 760
8021-288
( 8000+21)-(300-12) 8000+21-300+12= 8000-300 +21+12=(8000-300)+( 21+12) =7700+33=7733
