Add to find a total
A school buys 235 pencils and then 124 more. Altogether that is 359 pencils.
Combine the two parts to find the whole.
Year 3
Solve problems, including missing number problems, using number facts, place value, and more complex addition and subtraction
Choose and use addition or subtraction methods to solve one-step and two-step problems.
Lesson overview
Number - addition and subtraction
Word problems need us to decide what is happening to the number. If amounts are combined or increased, we often add. If amounts are taken away or we find a difference, we often subtract.
Subtract to find a difference
A jar holds 600 marbles. 148 are removed. 452 are left.
Subtraction helps us find what remains.
A missing number problem
___ + 120 = 470 means the missing number is 350.
Use the inverse to find the missing part.
Worked example
A theatre sold 278 tickets on Friday and 193 on Saturday. How many tickets were sold altogether?
- The word altogether tells us to combine the amounts.
- Add 278 and 193.
- 278 + 193 = 471.
- So 471 tickets were sold altogether.
Try it
Read the problem carefully and decide whether you need to add, subtract or use an inverse check.
Question 1
A shop sold 123 apples in the morning and 145 in the afternoon. How many apples were sold altogether?
Question 2
A tank held 500 litres. 160 litres were used. How much is left?
Question 3
Find the missing number: __ + 90 = 340
Question 4
Which operation matches the problem 'How many more'?
altogether
how many more
Question 5
A class read 146 pages on Monday and 154 pages on Tuesday. Which answer is correct?
Common mistakes
Watch for these when working through the lesson.
- Choosing the wrong operation from the story.
- Ignoring a number in a two-step problem.
- Forgetting to check whether the answer makes sense.
Related topics
These ideas fit closely with this lesson.
- Add and subtract numbers with up to three digits using formal written methods of columnar addition and subtraction.
- Estimate the answer to a calculation and use inverse operations to check answers.