Max Conquers the Castle: Subtract by Tens!

About this Grade 1 Subtracting Multiples Of 10 Drill

Subtracting multiples of 10 is a foundational skill that helps first graders see how our number system works in chunks and patterns. When children learn that 45 - 10 = 35, they're discovering that we can remove whole groups of ten without breaking apart ones—this is much easier than counting back one by one. This skill builds mental math speed and confidence, preparing them for two-digit addition and subtraction. In daily life, your child uses this when counting coins, sharing snacks in groups of ten, or thinking about time passing in ten-minute blocks. Mastering multiples of 10 also reduces counting anxiety; instead of counting backward from 45 one finger at a time, children learn to think "tens." This mental shortcut makes math feel manageable and fun at an age when number confidence is still developing.

What your student will practice

• Subtract one multiple of 10 from a two-digit number
• Recognize that subtracting 10 moves one place on the tens column
• Use concrete models or drawings to show subtraction of tens
• Solve word problems involving removal or loss of groups of 10

Common mistakes to watch for

The most common error is when children subtract 10 but accidentally change the ones digit. For example, a student might solve 34 - 10 and write 24 by removing 1 from the 3 in the tens place but also lowering the 4 to a 3—losing a one when they shouldn't. You'll spot this by looking for answers where both digits shifted. Another pattern: some children revert to counting backward on their fingers for every problem, which suggests they haven't internalized that the ones stay the same. Watch whether your student says "thirty-four, thirty-three, thirty-two..." instead of recognizing "30 - 10 = 20, so 34 - 10 = 24."