Find the mode of the following distribution:
Class interval
0-10
10-20
20-30
30-40
40-50
50-60
60-70
70-80
Frequency
5
8
7
10
28
20
The value of the given expression is ___ [[6×{(−6)×(−5)}]÷{28+(−14−5)}] +[{28×(−3)}÷(−2−2)] +[{(−4)×(−4)×6}÷(−4)]]