Understanding Number Bonds Subtraction
Number bonds are the building blocks of early arithmetic. When students learn to compose numbers to 20 and then reverse the process, they develop a solid foundation for subtraction. This article explains how Number Bonds Subtraction works, why it matters for Year 1 learners, and how Singapore Math approaches the concept.
Why Number Bonds Matter in Subtraction
Number bonds help children see numbers as flexible pairs rather than fixed facts. By recognizing that 13 can be split into 8 + 5, 7 + 6, or 10 + 3, a pupil can quickly answer questions such as “What is 13 − 5?” The answer becomes obvious: 13 − 5 = 8 because 5 is one part of the bond.
- Speed: Students retrieve subtraction facts faster when they can refer to known bonds.
- Confidence: Seeing multiple ways to make a number reduces anxiety around “hard” problems.
- Flexibility: Learners can choose the most convenient bond for a given subtraction task.
Core Concepts of Number Bonds Subtraction
1. Decomposing the Minuend
To subtract, first break the minuend (the number you are taking from) into two parts that include the subtrahend. For example, to solve 14 − 6, decompose 14 into 6 + 8. The answer is the other part, 8.
2. Using Complementary Pairs
Complementary pairs add up to a round number, such as 10 or 20. Knowing that 7 + 3 = 10 lets a student solve 10 − 7 quickly: the answer is the complement, 3. This technique is especially useful with the 5‑square and 10‑square number bond charts common in Singapore Math.
3. Borrowing Made Simple
When the subtrahend is larger than the ones digit of the minuend, borrowing is required. Number bonds make borrowing visual. For 23 − 9, think of 23 as 20 + 3. Since 9 is larger than 3, borrow 10 from the tens place, turning the problem into (20 − 10) + (13 − 9) = 10 + 4 = 14.
Teaching Number Bonds Subtraction to Year 1 Students
Effective instruction blends concrete materials, visual aids, and short, focused videos. Below is a step‑by‑step lesson outline that can be delivered by an online math tutor.
- Introduce the 5‑square and 10‑square charts. Show how each number from 0 to 10 can be paired with its complement to reach 5 or 10.
- Practice composing numbers to 20. Use manipulatives (counters or blocks) to build pairs such as 12 = 7 + 5, 15 = 10 + 5, etc.
- Transition to subtraction. Present a subtraction problem and ask the learner to find a bond that
