7 + 5 is the same as 5 + 7

Sam say 30 + 5 = 35 and John says 30 + 5 = 25.Who is correct? Sam or John?

17 - 5 is the same as 5 - 17

Jana has 17 crayons, her friend gave her 7 more. How many crayons does Jana have altogether?

49 - 7 =____

True or false:

34 - 8 = 25

Maria bought 29 balloons for her birthday party. Her brother took away 9 balloons. How many balloons are left with Maria?

56 - 0 = ____

30 + 0 = _____