Advanced Addition and Subtraction

1. Maya has $6$ red marbles and $4$ blue marbles. Jake has $4$ red marbles and $6$ blue marbles.

a) How many marbles does Maya have? $6 + 4 = \underline{\quad}$

b) How many marbles does Jake have? $4 + 6 = \underline{\quad}$

c) Did they both get the same answer? Why?

This shows that $6 + 4 = 4 + 6$. You can add numbers in any order!

2. A pet shop has $3$ kittens, $5$ puppies, and $7$ hamsters. Find the total number of pets.

a) First try: $(3 + 5) + 7 = \underline{\quad} + 7 = \underline{\quad}$

b) Now try: $3 + (5 + 7) = 3 + \underline{\quad} = \underline{\quad}$

c) Did you get the same answer both ways? $\underline{\quad}$

3. Think of subtraction as a missing-number addition problem. Fill in the blanks:

a) $12 - 5 = \underline{\quad}$ because $5 + \underline{\quad} = 12$

b) $14 - 8 = \underline{\quad}$ because $8 + \underline{\quad} = 14$

c) $11 - 7 = \underline{\quad}$ because $7 + \underline{\quad} = 11$

4. Is the equation true or false? Write true or false.

a) $3 + 4 = 7$ $\underline{\quad}$

b) $5 + 2 = 9$ $\underline{\quad}$

c) $8 = 8$ $\underline{\quad}$

d) $6 + 1 = 3 + 4$ $\underline{\quad}$

e) $10 = 6 + 5$ $\underline{\quad}$

5. A toy train has $4$ cars. Then $3$ more cars are added, and after that $6$ more cars are added. How many cars does the train have now?

a) Write the addition: $4 + 3 + 6 = \underline{\quad}$

b) Which two numbers would you add first to make it easier? (Hint: look for numbers that make $10$.)

c) Solve it your easy way: $\underline{\quad}$