bonsoir
a) 6 + 3 /10 + 4/100 = 600 /100 + 30/100 + 4/100 = 634 /100
b) 8 + 5/100 + 9/1000 = 8000 /1000 + 50/1000 + 9/1000 = 8059/1000
c) 3/10 + 2/100 + 1/1000 = 300/1000 + 20/1000 + 1/1000 = 321 /1000
fais le dernier, tu verras ainsi si tu as compris