Counting On — Definition, Formula & Examples
Counting on is an addition strategy where you start at the larger number and count forward by the amount of the smaller number to find the sum.
Counting on is a mental computation strategy for addition in which a student holds one addend (typically the greater) in memory and performs a forward count of successive integers equal to the other addend, arriving at the sum without counting from one.
How It Works
Pick the larger of the two numbers you are adding and keep it in your head. Then count forward from that number, one at a time, as many steps as the smaller number tells you. Each count adds one more. The number you land on is your answer. For example, to find , start at 8 and count: 9, 10, 11. You counted three times, so .
Worked Example
Problem: Find 5 + 3 using counting on.
Start at the larger number: Hold 5 in your mind. You will count forward 3 times.
Count forward: Starting from 5, count: 6 (that's 1), 7 (that's 2), 8 (that's 3).
Read the result: You landed on 8, so the sum is 8.
Answer: 5 + 3 = 8
Why It Matters
Counting on is one of the first strategies students use to move beyond counting every object from one. It builds number sense and lays the groundwork for more efficient strategies like making ten and using known facts, which are essential as students progress to multi-digit addition.
Common Mistakes
Mistake: Including the starting number in the count, getting an answer that is one too few (e.g., for 5 + 3, saying 5, 6, 7 and answering 7).
Correction: The starting number is your first addend, not your first count. Begin counting with the next number: 6, 7, 8.