Réponses

2014-05-21T18:20:47+02:00
999²
= (1000-1)²
= 1000²-2000+1
= 1000 000 -1999
= 998 001

2014-05-21T18:21:25+02:00
999² = (100 -1)² = 1000 000 - 2.1000 + 1 = 998001