Max Rescues Earth's Animals: Subtraction Sprint!

About this Grade 1 Subtraction Within 20 Drill

Subtraction within 20 is a cornerstone skill that helps six- and seven-year-olds build mathematical thinking and everyday problem-solving. At this age, children are developing the ability to decompose numbers and understand "taking away," which strengthens their number sense and prepares them for more complex operations. When your child can fluently subtract within 20, they're actually building two critical abilities: counting backward with confidence and understanding that numbers can be broken into smaller parts. These skills show up constantly in daily life—figuring out how many crayons are left after using some, determining how many more days until a birthday, or understanding change at a store. Mastering subtraction within 20 also reduces cognitive load, freeing up mental energy for word problems and multi-step thinking later on. Finally, this skill builds confidence; when children see themselves getting faster and more accurate, they develop a growth mindset about math itself.

What your student will practice

• Fluently solve subtraction facts with minuends up to 20
• Use counting back and number line strategies to solve subtraction
• Relate subtraction to "taking away" and "finding the difference" in real situations
• Write and solve subtraction equations with accuracy and speed

Common mistakes to watch for

Many Grade 1 students confuse the order of numbers in subtraction, writing the smaller number first or reversing what they're subtracting. Watch for students who count on instead of counting back (saying "15, 16, 17" when solving 17 − 2), which shows they haven't internalized the direction of subtraction yet. Some children also lose track while counting, especially with larger minuends, and may recount from 1 each time instead of using a strategy. You'll spot these errors when a child writes answers that are larger than the starting number or takes much longer than their addition work.