Max Rescues Lost Owlets: Add by Tens Sprint!

About this Grade 2 Adding Multiples Of 10 Drill

Adding multiples of 10 is a cornerstone skill for second graders because it builds number sense and prepares them for two-digit addition with regrouping. When children can quickly recognize that 20 + 30 = 50 without counting on their fingers, they develop mental math flexibility that makes all future arithmetic faster and more confident. At ages 7–8, students are moving away from counting-by-ones strategies toward place-value thinking, and mastering tens helps them understand that the tens place can be added independently from the ones place. This skill also appears constantly in real life—combining dollar bills, adding scores in games, or counting groups of objects—so students see immediate, practical value. Most importantly, fluency with tens scaffolds the jump to two-digit addition without regrouping and eventually to regrouping, which is critical by the end of second grade.

What your student will practice

• Add two multiples of 10 (10–90) with automaticity and accuracy
• Recognize that 10 + 10 = 20 and extend the pattern to larger multiples
• Apply adding multiples of 10 to simple word problems with concrete contexts
• Mentally decompose sums into tens and ones to check reasonableness

Common mistakes to watch for

The most common error is when students treat multiples of 10 as two separate single digits—for example, saying 20 + 30 = 50 but writing it as 2 + 3 = 5, losing track of place value. Another frequent mistake is students who forget the zero and write 20 + 30 = 5 or 20 + 10 = 3. You can spot this by listening to their explanation: if they say "two tens plus three tens equals five tens" but write "5" instead of "50," they haven't yet connected the language to the written form. A third pattern is skipping mentally and reverting to finger counting on every problem, which signals they haven't internalized the pattern yet.