Choose the correct answer and Fill in the blanks:
35--20=_____.55/15
Consider
35--2035+20=55
Hence, 35--20=55
0+-5=__.-5/+5
-1--1=__.0/-2
-1+___=+5.-6/+6
-72--90=_____.+18/-162
-4+(___)=-12.-8/+8