01.01 ADDITION EQUATIONS TO 10
What is the missing number in (2 + _ = 7)?
(2 is addend, 7 is sum, missing number is 5)
What is the missing number in (_ + 3 = 9)?
(3 is addend, 9 is sum, missing number is 6)
What is the missing number in (4 + _ + 1 = 9)?
(4 and 1 are addends, 9 is sum, missing number is 4)