Répondre :

1/ 15^2=10^2 + 2^2 =100+4=104
2/ 54^2=50^2 + 4^2 =2500+16=2516
3/ 199^2=200^2-1^2=40000-1=39999
4/ 999999/1000000=1000000/1000000 - 1/1000000 =1-10^-6