--- title: "Multiplying by Tens" description: "Multiply one-digit whole numbers by multiples of 10 in the range 10–90 using strategies based on place value and properties of operations" canonical: https://lightmysky.com/learn/mathematics/multiplying-by-tens-mt_isojCL9yy- source: https://lightmysky.com/learn/mathematics/multiplying-by-tens-mt_isojCL9yy-.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`. # Multiplying by Tens Multiply one-digit whole numbers by multiples of 10 in the range 10–90 using strategies based on place value and properties of operations Subject: Mathematics · Area: Multiplication & Division · Ages 8 to 9 Page: https://lightmysky.com/learn/mathematics/multiplying-by-tens-mt_isojCL9yy- ## Ready when they can - Calculate 7 × 30 = 210 by reasoning 7 × 3 tens = 21 tens = 210 - Explain why multiplying by a multiple of 10 adds a zero to the product - Use this skill to estimate products of larger numbers ## Lesson: Multiplying by Tens You already know facts like 6 × 4 = 24. Multiplying by a number such as 40 uses that same fact. Think of 40 as 4 tens. So 6 × 40 means 6 groups of 4 tens, which is 24 tens, or 240. *(drawing: Multiply the digits first, then think in tens: 7 × 3 = 21, so 7 × 30 = 210.)* **Example.** Look at 6 × 80. First multiply the digits: 6 × 8 = 48. Now think in tens: 80 is 8 tens, so 6 × 80 is 48 tens, which is 480. **Tip.** Always do the small multiplication fact first. Then place one zero at the end for the ten. **Recap.** Multiply the digits, then add one zero for the ten. ## Practice 15 questions on this page, each with its working shown. ## Needs first - [The three digits of a three-digit number](https://lightmysky.com/learn/mathematics/the-three-digits-of-a-three-digit-number-mt_aPBzD28_mT) - [Fluent multiplication and division facts](https://lightmysky.com/learn/mathematics/fluent-multiplication-and-division-facts-mt_WX30dzi4dt) ## Opens up - [Long multiplication](https://lightmysky.com/learn/mathematics/long-multiplication-mt_q9EaJc2FP8)