Question

20 x 1 + 20 x 2 + 20 x 3 + 20 x 4 + 20 x 5 + 20 x 6 + 20 x 7 + 20 x 8 + 20 x 9 + 20 x 10 =

Answer 1

=20x(1+2+3+4+5+6+7+8+9+10)

=20x55=1100

Answer 2

= 20 + 40 + 60 + 80 + 100 + 120 + 140 + 160 + 180 + 200 =(20 + 80)+ (40 + 60) + (120 +180) + (140 + 160) + 100 =100 + 100 + 300 + 300 + 100 = 200 + 300 + 300 + 100 = 500 + 300 + 100 = 800 + 100 = 900

Answer 3

=1100

k nha

Answer 4

1100 nhé