Year 2 - Maths
Solve problems by adding and subtracting tens and ones
Comparing, ordering and partitioning 2-digit numbers
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupils will compare two 2-digit numbers and partition a 2-digit number into 10s and 1s and position on a number line.
Lesson Summary
You will learn to solve problems that require the addition and subtraction of tens and ones.
Key Notes
- When tens and ones are combined to make a two-digit number, it can be represented as an addition equation.
- When a two-digit number is partitioned into tens and ones, it can be represented as a subtraction equation.
- We can use bar models to help us understand and represent a problem.
Vocabulary To Learn
- Addition: Finding the total, or sum, by combining two or more numbers.
- Subtraction: Taking one number away from another.
- Part: A piece or section of a whole
- Whole: All of something; complete.
Common Mistakes To Avoid
- Children may confuse addition and subtraction on bar models and in problems, so may add instead of subtracting or subtract instead of adding.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
When tens and ones are combined to make a two-digit number, it can be represented as an addition equation. When a two-digit number is partitioned into tens and ones, it can be represented as a subtraction equation.
2. Use this key word in a maths sentence and explain it clearly. 'Addition'
Finding the total, or sum, by combining two or more numbers. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Children may confuse addition and subtraction on bar models and in problems, so may add instead of subtracting or subtract instead of adding. Correction: Cuisenaire rods or strips of paper with numbers written upon them can be manipulated as bar models that represent a problem or equation. This way, the structure of the mathematics can be discussed.
More Lessons In This Unit
Browse all guides in the Year 2 Maths guide library.