ACT® · Math: Integrating Essential Skills
Multi-Step Arithmetic Word Problems
Multi-step arithmetic problems fail not from hard math but from stopping at the wrong step. The fix is to name the final target before you compute anything, then track each step against it.
A three-step problem has three places to go wrong: a wrong operation, a wrong order, or a right computation that answers the wrong question. That last one is the silent killer. You can do every step correctly and still pick the wrong number to circle, because the problem never asked for 'the total' — it asked for the change, or the difference, or the time including stops. A hard equation fails loudly, with a number that clearly doesn't work. A word problem fails quietly, with a number that looks perfectly reasonable and is simply not what was asked.
Before computing, underline or restate the actual target in your own words: 'I need the change from 50,' not 'I need the cost.' Then list the steps in the order the situation actually happens — discount before tax, driving time before adding stop time — and check after each one whether that step's result is the final answer or just an ingredient. Many problems are built so the natural last computation (the total cost, the driving time alone) is one step short of or one step past what's wanted.
This sits right next to rate and percent problems because those are the ingredients, not the topic itself. A discount-then-tax problem is just two percent calculations chained together; a drive-with-stops problem is just distance-over-speed plus added minutes. The new skill here is sequencing and target-checking, which is also exactly what two-worker rate problems demand: you compute each worker's rate, combine them, and still have to ask what quantity the question actually wants from that combined rate.
Key terms
- Target quantity
- The specific value the question asks for, which may require one more step after your main computation.
- Sequencing
- Doing the steps in the order the real-world situation requires, such as discount before tax.
- Combined rate
- The total work or distance rate when two or more workers or speeds act together, found by adding individual rates.
- Ingredient step
- A computed value that is needed to reach the answer but is not itself the answer.
Watch it explained
- How it worksHow do you pin down what a multi-step problem is actually asking for before computing anything?
- Worked exampleFind the total cost when a 45 dollar item is discounted 20 percent, taxed 7 percent, and bought 3 times.
- Worked exampleFind how long a 240 mile drive takes at 60 miles per hour with two 15 minute stops along the way.
- Common mistakeWhy isn't the answer to the last computation always the answer to the question?
- Going furtherWhat changes in a rate problem when two workers with different speeds start working at the same time?
Check yourself
End of topic.