Max Conquers the Beach Treasure Hunt: Adding Tens

About this Grade 2 Adding Multiples Of 10 Drill

Adding multiples of 10 is a cornerstone skill that helps second graders recognize patterns in our number system and build mental math fluency. When children understand that 20 + 30 is really "2 tens plus 3 tens," they're no longer memorizing isolated facts—they're seeing how numbers work together logically. This skill makes later addition and subtraction faster and more confident, reducing reliance on counting on fingers. At 7 and 8 years old, students are developing the abstract thinking needed to work with tens as units rather than individual ones. Mastering multiples of 10 also connects directly to real-world moments, like figuring out how much allowance or spending money they'll have over several weeks during summer vacation. These efficient strategies become the foundation for two-digit addition and even place value understanding that carries into third grade and beyond.

What your student will practice

• Recognize and identify multiples of 10 up to 100
• Add two multiples of 10 using tens place understanding
• Apply adding multiples of 10 to solve word problems
• Explain their thinking when combining groups of tens

Common mistakes to watch for

Second graders often treat multiples of 10 as regular single-digit problems, writing 20 + 30 = 5 because they only add the first digits without holding the zeros. Another frequent error is losing track of zeros altogether, answering 20 + 40 = 6 instead of 60. Some students may count by ones instead of counting by tens, which is slow and error-prone. Watch for answers missing zeros or answers that ignore the tens structure entirely—these signals show the child is not yet anchoring the "tens as units" concept.