Let's solve for Y in the given equation:

Y x 4 - Y : 4 = 1890

First, simplify the equation by combining like terms:

4Y - Y/4 = 1890

Now, let's get rid of the fraction by multiplying everything by 4:

4(4Y) - 4(Y/4) = 4(1890)
16Y - Y = 7560
15Y = 7560

Now, divide by 15 to solve for Y:

Y = 7560 / 15
Y = 504

Therefore, the value of Y is 504.