Subtract by Counting On - Up to 20
🧗♂️ Climbing the number ladder! When two numbers are very close together on the number line, counting UP is faster than subtracting down.
Do this: Read the concept below, then try the quiz or activity.
Concept
We usually subtract by counting backward. But what if the problem is 18 - 15 = ? Counting backward 15 spaces would take forever! Let's use a shortcut.
🎯 The "Distance" Shortcut: When the numbers are close, just find the distance between them by counting UP from the small number to the big number! 1. Start at the small number: Start at 15. 2. Count up to the big number: Say "16, 17, 18". 3. Count your steps: How many steps did you take? You took 3 steps! So, 18 - 15 = 3.
You turned a subtraction problem into a much faster addition puzzle!
Try it
Let's climb the ladder and count up!
Instructions: Start at the small number and count on to the big number to find the answer.
Problem 1: 19 - 17 = ? * Start at 17. Count up to 19: "18, 19". * How many steps? ___ * Answer: 19 - 17 = ___
Problem 2: 14 - 11 = ? * Start at 11. Count up to 14. * Answer: ___
Problem 3: 20 - 18 = ? * Answer: ___
Problem 4: 16 - 15 = ? * Answer: ___