Question

find the greatest number that divides 1470 and 1890 exactly without leaving a reminder​

Answer 1

You have to find the HCF (Highest common factor) for this. To find the hcf of these numbers you break them down:

1470= 2 x 3 x 5 x7 x7
1890= 2x3x3x3x5x7

Now, we can see that the numbers 2,3,5 and 7 are present in both 1470 and 1890. So to find the HCF of any 2 numbers you have to multiply the common numbers/factors.

Therefore, the greatest number that divides 1470 and 1890 = 2 x3 x5 x7 = 210