Max Discovers Hidden Paintings in the Art Gallery

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 mental math flexibility. When children master 20 + 30 or 40 + 10, they're learning that tens work just like ones—a crucial bridge to understanding place value. This skill appears everywhere in real life: counting coins in a piggy bank, tracking scores in games, or organizing items into groups of ten. At ages 6-7, children's brains are ready to move beyond counting by ones and see the elegance of working with groups. These drills strengthen their number sense and prepare them for two-digit addition later. By practicing adding multiples of 10, students develop confidence with mental math strategies they'll use throughout elementary school.

What your student will practice

• Fluently add two multiples of 10 within 100 using tens place understanding
• Recognize that 30 + 40 equals 3 tens plus 4 tens equals 7 tens
• Apply adding-multiples-of-10 to solve real-world word problems with groups
• Build automaticity so adding multiples of 10 becomes quick and automatic

Common mistakes to watch for

The most common error is children treating 20 + 30 like a counting problem, arriving at 52 or 53 instead of 50. This happens because they haven't yet internalized that the tens digit is the focus—they revert to counting on their fingers by ones. Watch for answers in the 40s or 50s when the correct answer should be a clean multiple of 10 like 50, 60, or 70. Another red flag is when a student writes 2 + 3 = 5, then writes 25 instead of 50—they're adding the digits but forgetting to multiply by 10.