Solve Addition and Subtraction Word Problems Using Equation
Key Concepts
Solve word problems to add and subtract values using equations
1. Find the unknown numbers
- We can use counters to find the missing number.
Example: Find the missing value in 15 – _____ = 8
2. True or false equations
- We can verify if a numerical equation is true.
Let us check whether the given equation is true or not.
3 + 6 = 4 + 5
Step 1: Find the value of each side of the equation.
Step 2: Compare the values on both sides of the equation.
Here, LHS = RHS
So, the given equation is true.
3. Equations with no operations
- Equations without any mathematical operations can also be true.
Example: Verify if the equation 3 = 3 is true.
Sol: Value at LHS is 3.
Value at RHS is also 3.
So, the equation is true.
4. Addition and subtraction using equations
Steve baked 35 muffins. Arthur baked 52 muffins. How many muffins did Steve bake less than Arthur?
Step 1: Make sense
Understand the problem given to find the missing value and place the given values in a table.
Step 2: You can write an addition or subtraction equation to find the missing value.
52 = _____ + 35
or
52 – 35 = ______
Therefore, Arthur made 17 muffins more than Steve.
Exercise
- James has 5 books. His mother gifts him 3 more books on his birthday. How many books does James have now?
- Tony and Chris together bake 15 cakes. If Tony alone baked 8 cakes, how many cakes did Chris bake?
- Amy has 11 more pencils than Rachel. If Rachel has 6 pencils, how many pencils does Amy has?
- Neo has 24 toys. He gave 12 toys to his sister. How many toys does he have now?
- Jen buys 5 sunflower plants and 8 tulip plants. How many plants did Jen buy in total?
- Christ wants to visit 13 states. He already visited 9 states. How many states does he need to cover more?
- Tom and Dennis scored 54 runs together in cricket. If Tom scored 28, what was Dennis’s score?
- Mother gave 4 chocolates to Alex. Later, his grandfather gave 5 chocolates to Alex. How many chocolates does he have in total?
- Tina had $37.50. She bought a book for $9.30 and had lunch for $12.15. How much money is left with her?
Concept Map :
What we have learned
- We can use addition or subtraction to find the missing numbers.
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