Max Rescues the Kitchen: Subtraction Sprint!

About this Grade 1 Subtraction Within 20 Drill

Subtraction within 20 is a foundational skill that helps six- and seven-year-olds make sense of the world around them. When your child can quickly figure out that 15 - 3 = 12, they're building mental math flexibility that supports both confidence and speed in problem-solving. At this age, students are developing their ability to decompose numbers and understand that subtraction is the inverse of addition—skills that are essential for all future math. This practice strengthens working memory and number sense, allowing children to move beyond counting on their fingers and toward genuine mathematical thinking. Real-world situations like figuring out how many crayons are left after sharing some with a friend, or how many cookies remain after eating a few, make subtraction concrete and meaningful. Mastery of subtraction within 20 removes a cognitive barrier, freeing up mental energy for more complex operations in second grade and beyond.

What your student will practice

• Fluently subtract single-digit numbers from two-digit numbers within 20
• Use strategies like counting back or number bonds to solve subtraction problems
• Recognize subtraction as the inverse operation of addition
• Apply subtraction to real-world problems and story situations

Common mistakes to watch for

Many Grade 1 students confuse the direction of subtraction and count forward instead of backward when they see a minus sign. You might notice a child saying 15 - 3 = 18 because they added instead, or they'll count up from 3 to 15 and lose track of how many steps they took. Another common error is starting from the wrong number—they might subtract 15 - 3 by beginning at 3 instead of 15. If your student is still using fingers to count down but making mistakes, watch whether they're setting up the starting number correctly on their fingers before counting back.