45-(-23)=45+23=78
26-39= - (39-26)= - 13
- 39,8 -(-23,5)= - 39,8+23,5= - 16,3
- 14,7 - 17,4= -(14,7+17,4)= - 32,1
3/7 -4= -(4-3/7)= - 3 4/7
- 11/12 -( -8/9)= -11/12 +8/9= - 33/36+32/36= - 1/36
-5 3/28+ 4 5/12= - 5 9/84+4 35/84= - 4 93/84+4 35/84= - 58/84= - 29/42
- 3 7/12 - 2 5/8= - 3 14/24 - 2 15/24= - 5 29/24= - 6 5/24