Fun math trick: multiply with lines

Yesterday I happened upon a TikTok video that demonstrates a very cool method for solving multiplication problems.

@mathswithmisschangWho uses Japanese multiplication?! 🤩 ##maths ##easymaths ##fyp ##foryoupage ##learnontiktok ##school ##gcse ##teacher ##multiplication♬ ROCKSTAR – DaBaby, Roddy Ricch

I couldn’t wait to share it with the kids. They were fascinated and turned the front porch into a giant chalkboard for practice sessions.

In this video, Miss Chang shows how carrying works:

@mathswithmisschangJapanese multiplication part 2 EXPLAINED with carrying over! 😝 ##maths ##easymaths ##learnontiktok ##fyp ##foryoupage ##school ##gcse♬ Backyard Boy – Claire Rosinkranz

This Youtube video walks through a few more problems, including some with three-digit numbers and carrying over. The method works with larger numbers but gets a bit unwieldy beyond three or four digits.

So cool!