Find the largest number of four digit which is exactly divisible by 18,25 and35

Ans me

18*25*35 = 15750, so the easy answer is too big

18 = 2 * 3^2
25 = 5^2
35 = 5*7
so the LCM is 2 * 3^2 * 5^2 * 7 = 3150
9999/3150 = 3.17
so 3*3150 = 9450 is the largest 4-digit multiple