What is subtraction?
The method of taking away two or more things is called Subtraction. It is denoted using the: Minus symbol (-)
How to teach subtraction?
Subtraction is the second operation students learn in math. It also forms a base for division. Thus concept clarity is a must while teaching subtraction to kids.
Here is the simple progression one can follow to teach subtraction:
Single-digit subtraction (without regrouping):
Step 1: Teach subtraction using pictures and objects.
To begin with, make students perform subtraction using blocks, toys, chocolates and objects that they like. Ask questions like: How many objects are left in total?
Step 2: Associate objects with numbers and perform subtraction.
Once students have mastered subtracting objects, make them start associating objects with numbers and start writing subtraction equations.
Step 3: Teach subtraction using the number line.
Once students understand the subtraction equation, make them subtract using the number line or number strips. With the help of a number line, students understand that subtraction requires counting backwards. Eg: To complete 5-3, they need to take 3 steps backwards on the number line.
Step 4: Simple word problems
Once students have understood the meaning of subtraction, it’s important they see its real-life application of it as well. Word problems not only raise the rigour but also are best for real-life scenario exposure. Give them, simple word problems like: I had 5 red balls, Toby threw 3 red balls away. How many red balls are left now?
Once students have mastered single-digit subtraction, it’s a good time to introduce double-digit subtraction to them.
Pre-requisites: Understanding of tens and ones in a number, place value
a) Double-digit subtraction without borrowing (with pictures):
The first step of double-digit subtraction is making students understand the concept using the place value block. When we directly move to subtract 2-digit numbers, students just mug up the process and do not actually understand the concept.
b) Double-digit subtraction without borrowing (with numbers):
Once students know to add 2 digits using the blocks, now they can move on to add numbers directly.
c) Double-digit subtraction with borrowing (with pictures)
Subtracting double-digit numbers with borrowing is a complex topic and students find it difficult initially. To have a clearer understanding, use the blocks again to teach 2-digit subtraction first.
When students subtract larger numbers with blocks, they actually understand the purpose behind regrouping and borrowing it to the next number on the place value.
d) Double-digit subtraction with borrowing (with numbers):
Once students have a good understanding of regrouping, introduce subtraction using numbers borrowing. Explicitly mention the steps to them so that they can have a clear understanding.
Introduction of zero through subtraction:
The best way to introduce zero to kids is through subtraction. Give them certain objects and keep taking away one item at a time. Finally, when no objects are left, say “We have zero objects now”.
Relation between addition and subtraction:
Addition and subtraction are the opposite.
We can undo an addition through subtraction, and we can undo a subtraction through addition.
Different ways of teaching subtraction:
Teaching through stories:
Teaching through games and activities:
a) Book cricket: This is one of the most popular games in elementary school. When students actually subtract runs needed to win or score they actually get extremely fluent with subtraction.
b) Shopping time: Whenever you go shopping, make children, subtract the change to be paid and see their excitement.