How do you add and subtract mixed numbers

You must have the same denominator, for example if you have 3/4+1/2 you would have to multiply 2/2 to 1/2 in order to get 2/4 so they can be added or subtracted or in "harder case like 2/3 - 2/7, you just have to multiply the 3*7 and the 7*3 to get the same denominator which in that case would be 21, I hope I explained that

You can first convert the mixed numbers into fractions and then operate them

if for example you have 3 4/3

to convert it you first multiply the whole by the denominator and then you add the nominator. The denominator is the same.

so 3 4/3=13/3