K-5 friendly lesson
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Subtracting 10

๐Ÿฆธโ€โ™‚๏ธ Subtracting 10 is actually one of the easiest math tricks ever! You don't even have to count.

Lesson 1

Concept

Subtracting 10 is awesome because it has a secret pattern. You don't need to count back 10 timesโ€”that would take way too long! ๐ŸŽฏ **The "Disappearing Ten" Trick:** Teen numbers (like 12, 15, or 18) are all made of a bundle of 10 and some extra "ones". * 15 is one "10" and five "1s". If you subtract 10 from 15, you are just taking the whole bundle of 10 away! What's left? Just the five "1s"! So, **15 - 10 = 5**. **Example: 19 - 10 = ?** Just take away the "1" at the front (which stands for 10). The answer is just the 9! **19 - 10 = 9**.

Try it

Make the 10 disappear! **Instructions:** Use the trick to solve these facts instantly. **Problem 1: 14 - 10 = ?** * Take away the bundle of 10. What is left? * Answer: ___ **Problem 2: 17 - 10 = ?** * Answer: ___ **Problem 3: 12 - 10 = ?** * Answer: ___ **Problem 4: 10 - 10 = ?** * Answer: ___