What you’ll learn
Find greatest common factor.
Key idea
Find the shared factors and compare them for greatest value.
Worked example
Enter the exact value or ordered values in the format requested below.
Find the greatest common factor of 6 and 30. Enter the largest factor dividing both exactly.
- The common factors are 1, 2, 3, 6.
- Their greatest entry is 6, so GCF(6,30)=6.
Answer: 6
Quick Check
Evaluate a worked attempt at find greatest common factor, identify the first invalid step, and provide the correction.
A student writes Step 1: 1 divides both 6 and 68. Step 2: therefore their GCF is 1. Identify the first invalid step and correct it.