Question

[Nam Sơn]

tính nhanh 
a, 27.49 + 61.49 + 49.12 + 100.51
b,43.27 + 93.43 + 57.61 + 59.57

Answer 1

[Hquynh]

\(a,=49\times\left(27+61+12\right)+100\times51=49\times100+100\times51=\left(49+51\right)\times100=100\times100=10000\\ -------------------\\ b,=43\times\left(27+93\right)+57\times\left(61+59\right)=43\times120+57\times120=120\times\left(43+57\right)=120\times100=12000\)

Answer 2

[Dora]

`a)27.49+61.49+49.12+100.51`

`=49.(27+61+12)+100.51`

`=49.100+100.51`

`=100.(49+51)=100.100=10000`

____________________________________

`b)43.27+93.43+57.61+59.57`

`=43.(27+93)+57.(61+59)`

`=43.120+57.120`

`=120.(43+57)`

`=120.100=12000`