A way to solve this is to give each fraction the same denominator:
1/2 = 3/6
1/3 = 2/6
so he spent 3/6 of his paycheck, then he puts the 2/6 to Charity so we add the fractions. That is 5/6. then we subtract 6/6 - 5/6 and get 1/6.
Jeff put 1/6 of his paycheck in the bank