Max Conquers the Marathon: Subtract by Tens Race

About this Grade 1 Subtracting Multiples Of 10 Drill

Subtracting multiples of 10 is a foundational strategy that helps first graders see patterns in our number system and build mental math confidence. When children can quickly subtract 10, 20, or 30 from a two-digit number, they're developing the number sense needed for all future math learning. This skill bridges concrete understanding (like removing 10 objects) with abstract thinking, preparing them for multi-digit subtraction in later grades. Kids this age are naturally curious about patterns, and working with multiples of 10 reveals how our base-10 system works. Whether organizing snacks, counting down laps in a race, or managing small allowances, removing groups of 10 happens constantly in real life. Mastering this skill also builds the automaticity that frees up mental energy for more complex problems.

What your student will practice

• Subtract 10, 20, and 30 from two-digit numbers with fluency
• Recognize that subtracting multiples of 10 changes only the tens place
• Apply skip-counting backward by 10s to solve subtraction problems
• Explain subtraction of multiples of 10 using place-value reasoning

Common mistakes to watch for

Many first graders incorrectly subtract from the ones place instead of the tens place—for example, solving 35 - 10 as 34 instead of 25. Others become confused when regrouping isn't needed and second-guess their answer. Watch for students who count backward by ones instead of recognizing the tens-place pattern, which shows they haven't yet grasped the structure of multiples of 10. If a child hesitates on every problem or uses fingers to count down 10 times, they need more concrete practice with bundled groups of 10 before moving forward.