Q = 29912015- 19991996 = (........1) - 19994.499
= (.........1) - (19994)499
= (.......1) - (.........1)499
= (.......1) - (.........1)
= (...........0) chia hết 10
=> Q = 29912015 - 19991996 chia hết 10 (đpcm)
Q=29912015 - 19991996
Q=(...1)-19994.499
Q=(...1)-(19994)499
Q=(...1)-(...1)499
Q=(...1)-(...1)
Q=...0 chia hết 10
Vậy Q chia hết 10