Max Rescues the Robot Factory: Subtract by Tens!

About this Grade 1 Subtracting Multiples Of 10 Drill

Subtracting multiples of 10 is a foundational skill that helps first graders build number sense and mental math fluency. When children master problems like 45 − 10 or 70 − 30, they're learning that the ones place stays the same while only the tens change—a pattern that makes larger subtraction problems feel less scary later. This skill directly supports their ability to count, make change, and solve word problems involving groups of objects. At ages 6-7, students are developing the cognitive ability to see numbers as made up of tens and ones, and practicing this drill strengthens that understanding. The confidence they gain here transfers to everyday situations like figuring out how many stickers remain after sharing some away. Most importantly, quick recall of these facts frees up their working memory for more complex problem-solving strategies they'll encounter throughout elementary school.

What your student will practice

• Subtract multiples of 10 from two-digit numbers with automaticity
• Recognize the tens digit changes while ones digit stays the same
• Apply subtraction of multiples of 10 to solve simple word problems
• Use mental math strategies to solve 30 − 10 or 80 − 20 efficiently

Common mistakes to watch for

The most common error is that first graders subtract from the entire number rather than just the tens place. For example, they might solve 35 − 10 as 35 − 1 = 34 instead of 25, treating the 10 as a single digit. Another frequent mistake is writing the answer in the wrong place value—answering 50 − 20 as 30 but placing it as 3 instead of 30. Watch for students counting down by ones instead of counting back by tens, which is slow and error-prone. If a child answers these problems inconsistently, they likely haven't yet internalized that only the tens place shifts.