Pre-K: Subtraction

Warm up with a quick recall on the board. Model 'take away' and 'difference' (counting up) with objects and a number line. For larger numbers, partition or use column subtraction with regrouping.

Subtraction is taking one amount away from another, or finding the difference between two amounts. It is the inverse of addition. Model the method clearly, thinking aloud:

• Model 'taking away' with objects, then 'finding the difference' by comparing two groups.
• Link every subtraction fact to an addition fact (fact families).
• Use a number line to count back.
• Introduce regrouping (borrowing) only after single-digit facts are secure.

Do the first few questions of the practice worksheet together, one child explaining each step. Check for understanding before releasing the class to work alone.

Students complete the worksheet independently. Hand out the three difficulty levels below so every child works at the right stretch.

Circulate and look for these, they are the usual sticking points:

• Subtracting the smaller digit from the larger in each column regardless of position.
• Struggling to borrow across a zero.
• Confusing 'take away' with 'difference'.
• Subtracting the smaller digit from the larger in each column regardless of order, instead of regrouping.

Pull the class back together. Ask one child to explain subtraction in their own words, pose a single check question everyone answers on a mini whiteboard, and name what you will build on next lesson.

Use the independent worksheet as the evidence. A child who can complete it accurately and explain one answer has met the objective; anyone who cannot needs the easier level and a short reteach next session.