Max Rescues Mermaids: Subtract Tens Sprint!

About this Grade 2 Subtracting Multiples Of 10 Drill

Subtracting multiples of 10 is a cornerstone skill that builds your child's number sense and mental math fluency. At age 7–8, students are learning that tens and ones are separate units—a concept that transforms how they tackle more complex subtraction later. When a child can quickly solve 45 − 20 or 67 − 30, they're developing the ability to break numbers apart strategically, which is exactly what they'll need for two-digit subtraction with regrouping in Grade 3. This skill also shows up constantly in real life: making change, calculating how many minutes are left in an activity, or figuring out how much snack money remains after a purchase. By practicing these patterns now, your child builds confidence and automaticity, freeing up mental energy for problem-solving rather than calculation.

What your student will practice

• Subtract multiples of 10 from two-digit numbers without regrouping
• Recognize that only the tens place changes when subtracting multiples of 10
• Apply mental math strategies to solve subtraction problems fluently
• Explain why the ones digit stays the same in these problems

Common mistakes to watch for

The most common error is when students subtract the entire multiple of 10 from the whole number rather than understanding place value. For example, they might solve 52 − 30 by counting backward 30 ones instead of recognizing they only need to subtract 3 tens, landing on 22. Another frequent pattern is students changing the ones digit when they shouldn't—answering 48 − 20 = 26 instead of 28. You'll spot this by looking at their written work or asking them to explain: if they're touching or erasing the ones place unnecessarily, they've likely lost track of place value.