top of page

3 Tips for Addition and Subtraction within 100: Primary 1 Math Mastery

The teacher is teaching her student addition and subtraction within 100.

As a parent, we want our children to perform well in all academic subjects, Mathematics is no exception. One essential Math topic for Primary 1 students is addition and subtraction within 100. This unit helps students develop their Math skills and lays the foundation for future mathematical concepts. However, many primary students struggle with mastering Addition and Subtraction within 100.

With the right strategies and activities, students can improve their Math skills and master this area. In this article, we will share with you 3 tips about Addition and Subtraction within 100. By implementing these strategies and engaging in fun Addition and Subtraction within 100 activities, your child can achieve Math mastery easily.

1. Using Number Line

the teacher is teaching one of her students to use number line for his math exam

Having a good grasp of the number line is essential for building a strong number sense in primary students. A number line is a visual tool that helps students understand the relationship between numbers and their positions on the line. This understanding lays the foundation for Addition and Subtraction within 100 and other mathematical concepts.

When counting mentally (both forward and backwards), students often make the mistake of including the starting number.


In 35 + 4, the common mistake is counting 35, 36, 37, 38 instead of counting 36, 37, 38, 39. To avoid this common error, visualising the number line can be helpful. Another tip is to always remember to count on the bigger number.

visualizing the number line to avoid common mistakes

2. Place Value Charts

Place value is a key concept for regrouping.


34 = ___ tens and ___ ones = 3 tens 4 ones

A good way to test their understanding is to ask them the following:

34 = 1 ten ___ ones = 1 ten 24 ones

36 = 2 tens ____ ones = 2 tens 14 ones

This will help them to understand regrouping in 2-digit addition and subtraction.

For example, in the following equation, 30 - 19 = ____

Regrouping in 2-digit addition and subtraction

9 ones cannot be subtracted from 0 ones.

So, we have to regroup the tens in 30.

30 = 3 tens 0 ones

= 2 tens 10 ones

Understanding place value will help with understanding the concept of regrouping in addition and subtraction.

3. Using Number Bonds

Number bonds are visual representations of a relationship between numbers. A number bond consists of two or more parts that combine to form a whole. It is a useful visual tool to help students understand the relationship between numbers and their parts.

Here's how to use number bonds to solve Addition and Subtraction problems within 100:


Subtract 6 from 28.

Step 1: Split into tens and ones.

Using Number Bonds to visually represents addition and subtraction

Step 2: Subtract the ones first.

8 − 6 = 2

Step 3: Add tens and ones.

20 + 2 = 22

Using number bonds to solve addition and subtraction problems helps students develop a deeper understanding of number relationships and builds a strong foundation for more difficult Math concepts.

Students developed their math skills with the help of the Primary Math Programme of  AGrader Learning Centre.

In conclusion, learning how to Add and Subtract within 100 is an important part of a student's early Math education. These three essential tips can help students develop a strong number sense and achieve Math mastery. Providing fun and engaging Primary 1 Addition and Subtraction Worksheets, helps students build a solid foundation in Math. Encourage your child to apply these tips, and you'll see him or her get better at Math and do better in school.

Explore our range of programs at AGrader Learning Centre, including our Primary Math Programme, which is designed to equip your child with the skills to master Math and boost their confidence in the subject.

Enrol your child today and watch their Math improve!

bottom of page