Subtracting 1-Digit from 2-Digit
Quick Theory: Subtracting 1-digit from 2-digit numbers strengthens place value understanding. Focus on subtracting from the ones column first. If needed, borrow from the tens column. This builds mental math speed and accuracy for everyday calculations.
What is Subtracting 1-Digit from 2-Digit?
This means taking a single-digit number (1–9) away from a two-digit number (10–99). Example: 45 − 7. You subtract from the ones place first and borrow if necessary.
How to Master Subtracting 1-Digit from 2-Digit Step by Step
- Look at the ones digit.
- If large enough, subtract directly.
- If smaller, borrow 1 ten.
- Subtract and simplify.
- Practice daily for speed.
Examples of Subtracting 1-Digit from 2-Digit
Example 1: 54 − 3 = 51
Example 2: 42 − 8 = 34
Example 3: 90 − 7 = 83
Basic Concepts
Understand place value: tens and ones. Borrowing means regrouping one ten into ten ones.
Advanced Techniques
Use mental math strategies like adjusting numbers: 52 − 9 can be done as 52 − 10 + 1.
Why It Matters
This skill improves confidence, builds number fluency, and prepares students for larger subtraction problems.
The Math Behind It
Formula: A − B where A is 2-digit and B is 1-digit. If ones(A) < B → borrow 1 ten.
FAQ
1. When do I borrow? When the ones digit is smaller than the number being subtracted.
2. Is this useful for mental math? Yes, it improves speed and accuracy.
3. What age group is this for? Typically Grade 1–3 students.
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