Question

tính bằng cách thuận tiện

39.8+60.2+21.8

 

 

Answer 1

`39.8+60.2+21.8`

`=8(39+21)+60.2`

`=8.60+60.2`

`=60(8+2)`

`=60.10`

`=600`

Answer 2

=8(39+21)+60*2

=60*(8+2)

=600

Answer 3

\(39.8+15.8+21.8=8.\left(39+15+21\right)=8.75=600\)

Answer 4

\(39.8+60.2+21.8\\ =8\left(39+21\right)+60.2\\ =8.60+2.60\\ =60.\left(8+2\right)\\ =60.10=600\)

Answer 5

\(39.8+60.2+21.8\)

\(=39.8+15.8+21.8\)

\(=8.\left(39+15+21\right)\)

\(=8.75\)

\(=600\)

Answer 6