Đáp án:
Giải thích các bước giải:
$\text{a) 5.23 + 35.41 + 64.65.}$
$\text{= 5.23 + 5.7.41 + 5.64.13.}$
$\text{= 5.23 + 5.287 + 5.832.}$
$\text{= 5.(23 + 287 + 832).}$
$\text{= 5.1142.}$
$\text{= 5710.}$
$\text{b) 29.87 - 29.23 + 64.71.}$
$\text{= 29.(87 - 23) + 64.71.}$
$\text{= 29.64 + 64.71.}$
$\text{= 64.(29 + 71).}$
$\text{= 64.100.}$
$\text{= 6400.}$
$\text{c) 19.27 + 47.81 + 19.20.}$
$\text{= 19.(27 + 20) + 47.81.}$
$\text{= 19.47 + 47.81.}$
$\text{= 47.(19 + 81).}$
$\text{= 47.100.}$
$\text{= 4700.}$
