Let the unknown number be n.
Then 20 + n = 30 : Subtract 20 from both sides gives :-
20 - 20 + n = 30 - 20 : n = 10
20+30+45 = 95
20
Counting 0 as a number, it's 20. Not counting 0, it's 30.
39
600/50 = 12
It is 255.
26
26
30
20+30+45 = 95
Prime numbers >20 and <30 are 23 and 29. Total value 52.
20
Counting 0 as a number, it's 20. Not counting 0, it's 30.
6,985
20+x
Add them up. 20, 21, 22, 24, 25, 26, 27, 28, 30
The numbers are 30 and 20.