Carlos has 58 pencils. What is the value of the digit 5 in this number?

Read it aloud: fifty-eight. The 5 stands for "50" or fifty.

another way to look at it is to count the position at which 5 is: it's the second position from the right. In our counting system, the places have the value of 10 to the power of (number of the position minus 1) : the position is 2: so the value is 5 (the digit) * 10^ (2-1), which is 5*10^ (1) = 5*10, which is 50

fifty is the value in your question