How can you find the greatest common factor using a calculator?

Answer 1

Unless your calculator has a key for it, the only method I know is awkward. Example : Take 24 and 114. Divide 114 ÷ 24. It gives 4.75. Subtract the integer part (4) to keep only the fraction part (0.75). Remultiply by 24. This gives 18. Do the same thing with the smallest number 24, and the new number 18. Divide 24 ÷ 18. It gives 1.33333333. Subtract the integer part (1) to keep only the fraction part (0.3333333). Remultiply by 18. This gives 12. Do the same thing with the smallest number 18, and the new number 12. Divide 18 ÷ 12. It gives 1.5. Subtract the integer part (1) to keep only the fraction part (0.5). Remultiply by 12. This gives 6. Do the same thing with the smallest number 12, and the new number 6. Divide 12 ÷ 6. It gives 2.0. When there is no fraction part left, the game is over, and the smallest number found is the GCF. So the answer is 6. Another example with 17 and 35. Divide 35 ÷ 17. It gives 2.05882352941. Subtract the integer part (2) to keep only the fraction part (0.05882352941). Remultiply by 17. This gives 1. Start again with the smallest number 17, and the new number 1. Divide 17 ÷ 1. It gives 17.0. There is no fraction part left, so the answer is the smallest number found, which is 1. When two numbers have no common factors, the answer will always be 1, since you can divide anything by 1.