Max Rescues Butterflies: Add Tens in the Lab!

About this Grade 1 Adding Multiples Of 10 Drill

Adding multiples of 10 is a foundational skill that helps first graders recognize patterns in our number system and build toward two-digit addition with confidence. When children grasp that 20 + 30 = 50, they're not just memorizing facts—they're understanding how tens work together, which is essential for place value concepts. This skill appears constantly in real life: counting money in dimes, organizing groups of 10 objects, or measuring in tens on a ruler. At ages 6-7, children's brains are primed to spot patterns, and multiples of 10 feel intuitive because they're predictable. Mastering this creates a springboard for mental math strategies, reduces reliance on counting on fingers, and builds the automaticity needed for faster computation. When your child can quickly see that 10 + 40 = 50 without counting by ones, they've unlocked a mental shortcut that makes all future math feel more manageable and less overwhelming.

What your student will practice

• Recognize and fluently add two multiples of 10 within 100
• Understand that tens can be added just like ones
• Apply adding-multiples-of-10 to solve simple word problems
• Build automaticity with mental math strategies using tens

Common mistakes to watch for

The most common error is when first graders treat multiples of 10 like single-digit numbers—for example, saying 20 + 30 = 5 instead of 50. This happens because they see the numbers 2 and 3 and add those, ignoring the zeros. Another frequent mistake is counting by ones instead of recognizing the pattern (1, 2, 3... instead of 10, 20, 30). Watch for students who write the correct tens digit but add the ones place too (like 20 + 30 = 53). These patterns signal the child hasn't yet abstracted that 'two tens plus three tens equals five tens.'