Chu so tan cung la 4 .
Khi giam di 4 don vi thi so don vi thi so do vua chia het cho 5 , vua chia het cho 8 .
Goi so nay la x
\(\frac{x}{5}-\frac{x}{8}=426\)
\(\frac{3x}{40}=426\)
\(3x=426.40\)
\(3x=17040\)
\(x=17040:3\)
\(x=5680\)
So can tim la :
5680+4=5684
DS:5684
**** nhe