Question

Tính nhanh:

6+8+12+14...42+44

Answer 1

6+8+12+14+...42+44

=6+8+12+14+16+18+20+22+24+26+28+30+32+34+36+38+40+42+44

=(6+44)+(8+42)+(12+38)+(14+36)+(16+34)+(18+32)+(20+30)+(22+28)+(24+26)

=  50    +50      +50       +50        +50       +50       + 50       +50        +50

=50x9

=450

Answer 2

Số số hạng:  \(\left(44-6\right):2+1=20\left(số\right)\)

Tồng \(\left(44+6\right)\times20\div2=500\)

Answer 3

=(6+44)+(42+8)+(12+...)+(14+...)

=(50+50)+(12+14+...)

=100x2

=200