Tim 1 so biet rang neu viet them chu so 0 vao ben phai so do thi so do tang len 405
tim so be nhat sao cho khi viet so do vao ben phai so 2009 thi duoc so co sau chu so chia het cho 125.
bai 2; tim x
184250 : (x nhan 134 ) = 125
tim mot so biet rang so do co hai chu cong voi so 79 bang 200
khi thuc hien phep cong 2 so thap phan 1 ban hoc sinh da viet nham dau phay cua 1 so hang sang ben trai 1 chu so nên tong tim duoc la 36,074 . Tìm 2 số hang do biet tổng dung la 149,96
tim so tu nhien co 3 chu so biet rang khi chia so do cho 17 thi duoc so du la 8 con chia so do cho 25 thi duoc so du la 16
tim mot phan so bang phan so 3/4 biet rang neu lay tu so cua phan so do cong voi nam thi duoc phan so bang 4/5
tim mot so biet neu gap so do nen 5 lan thi bang 300
Tim so biet rang so do gap len 9 lan roi bot di 16 thi duoc 20
tim mot so co hai chu so biet hieu cua chu so hang chuc va chu so hang don vi bang 5 va tich cua hai chu so bang 24