Multi-step addition & subtraction problems
Theory
Multi-step addition and subtraction problems are a Year 4 maths problem-solving skill: word problems that need more than one calculation. This page shows how to turn each action into add or subtract, work through the steps in order, use a bar model to see the parts and the whole, and work backwards to find a starting amount for numbers to 1000 and money in dollars. Curriculum: VC2M4N09 / AC9M4N08.
A multi-step problem is a word problem that needs more than one step. You add or subtract two or three times before you reach the answer. Reading carefully matters just as much as the calculating.
The trick is to turn each action into add or subtract. Words like join, more, altogether, total and arrive mean add. Words like spend, leave, get off, give away and sold mean subtract. Then you work through the steps in order, keeping a running total after each one.
A bar model is a picture that helps you plan. The whole is one long bar and the parts sit underneath it. When you know the whole and some parts, you subtract to find a missing part. When you know all the parts, you add to find the whole.
Multi-step problems do not use a formula, but these word links help you write the number sentence for the whole story.
How to solve a multi-step problem
- Read to the end. Read the whole story before you start so you know how many steps there are.
- Match each action. Turn each part of the story into add or subtract, using the meaning, not just a key word.
- Work in order. Do the first step, then use that answer in the next step, keeping a running total.
- Compare when asked. For "how many more", "is it enough" or "which statement is true", work out each amount first, then subtract to compare.
- Check it. Work backwards or ask if the answer makes sense for the story.
| \(\text{get off}\) | \(\to\) | \(-38\) |
| \(\text{get on}\) | \(\to\) | \(+54\) |
| \(162 - 38 + 54\) | \(=\) | \(178\) |
The sentence is \(162 - 38 + 54\), which gives \(178\).
| \(176 + 158\) | \(=\) | \(334\) |
| \(334 - 290\) | \(=\) | \(44\) |
Add the two batches, then subtract what was sold: \(44\) rolls are left.
| \(180 - 75\) | \(=\) | \(105\) |
| \(105 - 46\) | \(=\) | \(59\) |
Take away each amount she spent: \(\$59\) is left.
| \(60 + 35\) | \(=\) | \(95\) |
| \(95 + 40\) | \(=\) | \(135\) |
Add the spending back to what is left: she started with \(\$135\). Check: \(135 - 60 - 35 = 40\).
Common pitfalls
Frequently asked questions
What is a multi-step word problem?
A multi-step word problem needs more than one calculation to solve. You usually add or subtract two or three times, keeping a running total, before you reach the final answer.
How do you solve a two-step word problem?
Read the whole story first. Turn each action into add or subtract, do the first step, then use that answer in the second step. Working in order keeps a running total.
Do I add or subtract in a word problem?
Look at what is happening. Words like join, more, altogether and arrive mean add. Words like spend, leave, get off and sold mean subtract. Some problems use both.
How do you find the starting number in a word problem?
Work backwards and undo each step. If an amount was added, subtract it back. If an amount was taken away, add it back. Spending \(\$60\) and \(\$35\) and having \(\$40\) left means you started with \(60 + 35 + 40 = 135\).
What is a bar model in maths?
A bar model is a picture that shows the whole amount as one long bar and the parts as smaller bars underneath. It helps you see which parts to add and which to subtract to find a missing amount.
Why do I keep getting multi-step problems wrong?
The most common reason is stopping after one step. Read to the end, do every step, and keep the actions in the same order as the story. Checking your answer by working backwards helps too.