To add or subtract fractions, you need to make them have the same denominator, either by multiplying or dividing the numerator and denominator of the fraction by the same number.
3/4=9/12(multiply 3)
1/6=2/12(multiply 2)
9/12-2/12=7/12
Hence,
3/4-1/6=7/12
Hope this helps you to understand. :)
