Răspuns :
a=1+2+3+...+100+51×101 =
=100×(100+1)/2 + 51 ×101=
=50 × 101 +51 × 101= 101(50+51)=101 ×101= 101²
=100×(100+1)/2 + 51 ×101=
=50 × 101 +51 × 101= 101(50+51)=101 ×101= 101²
a = 100 * (100 + 1) : 2 + 51 * 101
a = 101 * 50 + 51 * 101
a = 5050 + 5151
a = 10 201
a = 101 * 50 + 51 * 101
a = 5050 + 5151
a = 10 201