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

Toán Lớp 6: 1. Chứng minh rằng: a)Nếu ab+cd+eg chia hết cho 9 thì abcdeg chia hết cho 99

Toán Lớp 6: 1. Chứng minh rằng:
a)Nếu ab+cd+eg chia hết cho 9 thì abcdeg chia hết cho 99

Comments ( 1 )

  1. Ta có:
    $\overline{abcdeg}$=$\overline{ab}.$10000+$\overline{cd}$.100+$\overline{eg}$
    =9999.$\overline{ab}$+$\overline{ab}$+99.$\overline{cd}$+$\overline{cd}$+$\overline{eg}$
    =(9999.$\overline{ab}$+99.$\overline{cd}$)+($\overline{ab}$+$\overline{cd}$+$\overline{eg}$)
    Vì 9999 ; 99 $\vdots$99 và $\overline{ab}$+$\overline{cd}$+$\overline{eg}$ $\vdots$ 9⇔$\overline{ab}$+$\overline{cd}$+$\overline{eg}$ $\vdots$ 99 nên(9999.$\overline{ab}$+99.$\overline{cd}$)+($\overline{ab}$+$\overline{cd}$+$\overline{eg}$)  $\vdots$ 99

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