If t = the tens digit and u = the ones digit, which expression shows the value of interchanging the digits in a two digit number?

T = tens digit

u = ones digit.

If we made it into a value, that would be equal to

10t + u

if we want to interchange the values of the two digits, then

tens = 10*u

ones = t / 10

Then getting the value of the digit after interchanging

10u + (t/10)