Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

222-9+11+12:2*14+14 = ? ( )

Toán Lớp 6: cho abcd chia hết cho 99 chứng tỏ (ab +cd) chia hết cho 99

Toán Lớp 6: cho abcd chia hết cho 99
chứng tỏ (ab +cd) chia hết cho 99

Comments ( 2 )

  1. Ta có: 
    $\overline{abcd}$ $\vdots$ $\text{99}$
    $\Rightarrow$ $\overline{abcd}$ $\text{.100}$ $\overline{cd}$ $\vdots$ $\text{99}$
    $\overline{ab}$ $\text{99+}$ $\overline{ab}$ + $\overline{cd}$ $\vdots$ $\text{99}$
    $\text{Vì}$ $\overline{ab}$ $\text{.99}$ $\vdots$ $\text{99}$ $\text{nên}$ $\overline{ab}$ $\text{+}$ $\overline{cd}$ $\vdots$ $\text{99}$

  2. Giải đáp:
    Ta có :
    $\overline{abcd}$ = $\overline{ab}$.100+ $\overline{cd}$
    = $\overline{abab}$.99+ $\overline{cd}$ + $\overline{ab}$
    Do $\overline{abcd}$ $\vdots$ 99
    -> $\overline{abab}$.99+ $\overline{cd}$ + $\overline{ab}$ $\vdots$ 99
    Lại có $\overline{abab}$.99 $\vdots$ 99
    -> $\overline{cd}$ + $\overline{ab}$ $\vdots$ 99
    -> đpcm.
     

Leave a reply

222-9+11+12:2*14+14 = ? ( )