Max Rescues Forest Animals: Add by Tens!

About this Grade 1 Adding Multiples Of 10 Drill

Adding multiples of 10 is a cornerstone skill that helps six- and seven-year-olds see patterns in our number system. When children recognize that 20 + 30 follows the same logic as 2 + 3, they're building mental math confidence and preparing for two-digit addition with regrouping. This skill reduces counting on fingers and supports faster, more flexible thinking about numbers. In everyday moments—counting crayons in boxes of 10, combining groups of coins, or organizing items at a nature reserve into equal sets—children apply this pattern naturally. By mastering multiples of 10, students develop number sense that makes later arithmetic feel logical rather than memorized. They're also strengthening their understanding that the ones place stays the same while only the tens place changes, a foundational insight for place value.

What your student will practice

• Recognize and identify patterns when adding tens to other tens
• Mentally add two multiples of 10 without counting by ones
• Apply adding-multiples-of-10 to solve one-step word problems
• Use place value understanding to explain why 30 + 20 equals 50

Common mistakes to watch for

Many first graders count by ones instead of recognizing the tens pattern: they'll say 30 + 20 by counting 31, 32, 33... all the way to 50, missing the leap. Another common error is forgetting the zero: writing 5 instead of 50 for 30 + 20. You'll spot this when a child gets the 'tens digit' correct in their head but drops the zero on paper. Some children also mix up which number stays the same—they might change the ones place instead of keeping it at zero. If you see slow counting, ask the child to show you with their fingers or objects; it's a sign they haven't yet grasped the pattern.