Question

(1+2+3+4+....+9)x(21x5-21-4x21

tính nhanh

Answer 1

\(\text{(1+2+3+4+....+9)x(21x5-21-4x21}\))

\(=\text{(1+2+3+4+....+9)x}\) \(\left(105-21-84\right)\)

\(=\left(1+2+3+4+....+9\right)\times0\)

\(=0\)

\(#Siliver\)

Answer 2

(1+2+3+4+....+9)x(21x5-21-4x21

=(1+2+3+4+....+9)x (105−21−84)

=(1+2+3+4+....+9)×0

=0

Answer 3

(1 + 2 + 3 + 4 + ..... + 9) . (21 . 5  - 21 - 4 . 21)

= (1 + 2 + 3 + 4 + .....+ 9) . [ 21(5 - 1 - 4)]

= (1 + 2 + 3 + 4 + ..... + 9) . (21 . 0)

= (1 + 2 + 3 + 4 + ...... + 9) . 0

= 0