Question

Tính 1+7+8+15+23+.......+259

Answer 1

1+7+8+15+23+....+259

=1+7+8+15+23+38+61+99+160+259

=671

Answer 2

=1+7+8+15+23+38+61+99+160+259

=[1+99]+[7+23]+[61+259]+8+15+38+160

=100+30+320+8+15+38+160

=671

phù!!!!!!!!!!!!!!!!!

nhé công chúa sakura dễ thương!