Answer:
(a) 7 / Reflective property
(b) 0 / additive property of zero
(c) 2 / Addition property of equality
Explanation:
(a) You are finding what number would make both sides of the equation equal. So we can symplify the right end of the equation, (7+3) to get 10. At this point we would just have to find out 3 + ? = 10. The next step to take would be 10 - 3 to find the missing number. Which is how we get 7.
(b) You are trying to find 3 + ? would equal 3. So we can write it out as 3 + ? = 3. So we would subtract 3 from both sides to get ? = 0. Which means that our missing number is 0.
(c) Add all the known numbers that are shown. On the left you get 13 and on the right you get 11. We can then write this out as 13 = ? + 11. From here we subtract 11 from both sides to get 2 = ?. So our missing number would be 2.