22/23 - 18/28 + 5/23=?
22/23-18/23+5/23=9/23 8 7/9+(7 5/9-4 4/9)=8 7/9+3 1/9=11 8/9 11 2/19-(3 17/19+6 14/19)=9/19 1)3 17/19+6 14/19=9 31/19=10 12/19 2)11 2/19- 10 12/19=10 21/19-10 12/19=9/19