Max Conquers the Midnight Sun Math Challenge

About this Grade 2 Subtraction With Borrowing Drill

Subtraction-with-borrowing (also called regrouping) is a turning point in second-grade math. At seven and eight years old, students are ready to move beyond simple subtraction facts and tackle two-digit problems where the ones place doesn't have enough to subtract from. This skill bridges concrete understanding of place value with abstract problem-solving—a critical leap in mathematical thinking. When your child borrows from the tens place, they're learning that 10 ones equals 1 ten, deepening their grasp of how our number system works. Mastering regrouping now prevents confusion later with larger numbers and multiplication. In daily life, borrowing appears when making change, splitting toys fairly, or even understanding how time works—like when the midnight sun finally sets, marking the end of an Arctic day and the need to "regroup" your schedule.

What your student will practice

• Identify when borrowing is needed by comparing digits in the ones place
• Regroup tens into ones and adjust the tens digit accordingly
• Solve two-digit subtraction problems using the borrowing method
• Check answers using addition to verify subtraction accuracy

Common mistakes to watch for

The most common error is students forgetting to reduce the tens digit after borrowing. For example, in 32 − 15, they correctly change 2 ones to 12 ones but forget to cross out the 3 tens and write 2, leading to wrong answers like 27 instead of 17. Watch for papers where the tens column still shows the original digit after regrouping. Another frequent mistake is borrowing when it's not needed—a child might borrow in 34 − 12 even though 4 > 2. Ask your child to "check the ones first" to see if borrowing is actually necessary.