Max Conquers the April Fools Joke Factory!

About this Grade 1 Subtracting Multiples Of 10 Drill

Subtracting multiples of 10 is a cornerstone skill that helps first graders develop number sense and mental math fluency. When children can quickly solve problems like 35 − 10 or 50 − 20, they're building the foundation for two-digit subtraction and strengthening their understanding of place value. At ages 6–7, students are developing the ability to see numbers as groups of tens and ones, and practicing these specific problems reinforces that crucial insight. This skill also builds confidence with numbers and reduces reliance on counting on fingers, moving students toward more efficient problem-solving strategies. Real-world examples—like removing 10 stickers from a sheet of 40, or counting back by tens on a number line—make the concept tangible. Mastering subtracting multiples of 10 prepares children for the more complex subtraction they'll encounter in second grade.

What your student will practice

• Fluently subtract multiples of 10 from two-digit numbers without counting
• Recognize and apply place value understanding to tens and ones
• Use mental math strategies to solve subtraction problems efficiently
• Explain subtraction using number lines or ten-frames

Common mistakes to watch for

The most common error is that students count down by ones instead of counting by tens, turning a 5-second problem into a 20-second ordeal—and often arriving at the wrong answer due to lost count. Another frequent mistake occurs when students subtract the wrong digit; for example, in 43 − 20, they might subtract 2 from 3 instead of recognizing that they're removing 2 tens. Watch for students who write 43 − 20 = 23 instead of 23, or who seem confused about whether the ones place should change. These errors signal that the student hasn't yet internalized that subtracting 10, 20, or 30 only affects the tens place.