Use Ten to Subtract
🦸♂️ Ten is your superpower! When you have a tough subtraction problem in the teens, you can use the number 10 as a stepping stone to find the answer fast.
Concept
Numbers like 15 or 16 can be tricky to subtract from directly. But every "teen" number has a hidden 10 inside it! We can use this to our advantage. 🎯 **The "Step on 10" Strategy:** **Example: 15 - 8 = ?** This is a hard fact. But let's break the 8 into two smaller steps. 1. **Step 1: Get down to 10.** To get from 15 down to 10, you have to subtract 5. 2. **Step 2: Figure out what's left of the 8.** We already subtracted 5. That means we still need to subtract 3 more (since 5 + 3 = 8). 3. **Step 3: Subtract from 10.** Now just do 10 - 3. What is the answer? 7! So, **15 - 8 = 7**. We used 10 as a resting spot halfway through the jump!
Try it
Let's practice the "Step on 10" strategy! **Instructions:** Break the second number into two parts. Use the first part to get down to 10! **Problem 1: 14 - 6 = ?** * Step 1: Take away 4 to get to 10. (14 - 4 = 10) * Step 2: The 6 was made of 4 and 2. We still need to subtract 2. * Step 3: 10 - 2 = ___ * Answer: 14 - 6 = ___ **Problem 2: 13 - 5 = ?** * To get from 13 down to 10, take away ___. * We still need to take away ___ more. * 10 - ___ = ___ * Answer: 13 - 5 = ___ **Problem 3: 16 - 7 = ?** * Answer: ___ **Problem 4: 15 - 9 = ?** * Answer: ___