--- title: "Adding and subtracting (age 9+)" description: "Solve addition and subtraction multi-step problems in contexts, deciding which operations and methods to use and why" canonical: https://lightmysky.com/learn/mathematics/adding-and-subtracting-age-9-mt_-F_Lv_apzH source: https://lightmysky.com/learn/mathematics/adding-and-subtracting-age-9-mt_-F_Lv_apzH.md retrieved: 2026-10-19 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Adding and subtracting (age 9+) Solve addition and subtraction multi-step problems in contexts, deciding which operations and methods to use and why Subject: Mathematics · Area: Addition & Subtraction · Ages 9 to 10 Page: https://lightmysky.com/learn/mathematics/adding-and-subtracting-age-9-mt_-F_Lv_apzH ## Ready when they can - A school collects 12,450 bottles in Week 1 and 8,372 in Week 2; their target is 25,000. How many more do they need? - Choose between mental and written methods for each step and explain why - Solve a three-step problem involving addition and subtraction of five-digit numbers ## Lesson: Multi-step addition and subtraction Some problems take more than two steps to solve. Read the story slowly, one part at a time. At each step, ask yourself: am I adding or subtracting here? And should I work it out in my head, or write it down? Mentally, turn 46 minus 19 into 46 minus 20, then add 1 back. On paper, line up the columns, start from the ones place, and borrow when the top digit is smaller. Build the biggest tens digit, subtract the smallest digit. *(drawing: A school collects bottles over two weeks. How many more do they need to reach the target of 25,000?)* **Example.** A school collects 12,450 bottles in Week 1 and 8,372 in Week 2. Their target is 25,000 bottles. Step 1: add the two weeks. 12,450 + 8,372 = 20,822. That's a big sum with regrouping, so it helps to write it in columns. Step 2: subtract from the target. 25,000 minus 20,822 = 4,178. The school still needs 4,178 more bottles. **Tip.** Look at the numbers before you pick a method. Round, simple numbers like 500 and 120 are quick to work out in your head. Numbers with several digits, or ones that need regrouping, are easier to get right on paper. **Example.** A class is raising money for a trip. They start with 15,000 pounds saved. Step 1: a bake sale raises 12,500 pounds. 15,000 + 12,500 = 27,500. That's easy to do in your head because both numbers are round. Step 2: they spend 8,750 pounds on bus tickets. 27,500 minus 8,750 = 18,750. This one is easier to write down, because of the regrouping. Step 3: they spend 3,200 pounds on entry tickets. 18,750 minus 3,200 = 15,550. No regrouping is needed, so mental works fine. The class has 15,550 pounds left. **Recap.** Break a multi-step problem into stages, decide add or subtract at each one, and choose mental or written based on how tricky the numbers are. ## Practice 11 questions on this page, each with its working shown. ## Needs first - [Two-step addition and subtraction problems](https://lightmysky.com/learn/mathematics/two-step-addition-and-subtraction-problems-mt_CDa5AVakLE) - [Mental addition and subtraction (age 9+)](https://lightmysky.com/learn/mathematics/mental-addition-and-subtraction-age-9-mt_MWXPiaTnEu) - [Fluent addition and subtraction (age 9+)](https://lightmysky.com/learn/mathematics/fluent-addition-and-subtraction-age-9-mt_Yw1_4Nfsql) ## Opens up - [Adding and subtracting (age 10+)](https://lightmysky.com/learn/mathematics/adding-and-subtracting-age-10-mt_M1tnXqmYbn)