Question

tính bằng cách thuận tiện nhất

15 x \(\dfrac{2121}{4343}\)+15 x \(\dfrac{222222}{434343}\)

Answer 1

`= 15 xx (2121:101)/(4343:101) + 15 xx (222222:10101)/(434343:10101)`

`= 15 xx 21/43 + 15 xx 22/43`

`= 15 xx (21+22)/43`

`= 15 xx 1`

`= 15`.

Answer 2

`15xx2121/4343+15xx222222/434343`

`=15xx21/43+15xx22/43`

`=15xx(21/43+22/43)`

`=15xx43/43=15`

Answer 3

`15xx2121/4343+15xx222222/434343`

`=15xx(2121/4343+222222/434343)`

`=15xx(21/43+22/43)`

`=15xx1`

`=15`

Answer 4

`15xx2121/4343+15xx222222/434343`

`=15xx(2121/4343+222222/434343)=15xx( (2121xx1000)/434343+222222/434343)`

`=15xx(212121/434343+222222/434343)=15xx1=15`

Answer 5

15 x 2121/4343 + 15 x 222222/434343

=> 15 x 21/43 + 22/43

=> 15 x (21 + 22) : 43

=> 15 x 1 

=> 15