Cooking requires a firm grasp of fractions due to the measuring required to follow a recipe correctly. Whether you are following a recipe or have another reason for halving a fraction, if you need to divide a fraction in half, the process is remarkably simple. Follow the basic formula for dividing a fraction by two, and you can then continue with your mission -- culinary or otherwise.
Write the fraction you wish to divide on a sheet of paper.
Create a simple multiplication problem to half the fraction. For example, if you wish to halve the fraction 5/7, write “* 2” beside the denominator “7.” There is no operation to perform to the numerator.
Multiply the denominator by 2 to halve the fraction. Using the same example, 7 * 2 = 14. This means that half of 5/7 is 5/14.
To halve a mixed number, determine whether the whole number is even or odd. If the whole number is even, divide it in half and multiply the denominator of the fraction by 2. For example, to halve 4 3/5, divide 4 / 2 = 2. Multiply 5 * 2 = 10. The answer is 2 3/10. If the whole number is odd, divide it in half and round the decimal down to the nearest whole number. Add the numerator and denominator of the fraction together to get the new numerator. Multiply the old denominator by 2 to get the new denominator. For example, to halve 3 1/2, divide 3 / 2 = 1.5 (round down to 1). Add 1 + 2 = 3. Multiply 2 * 2 = 4. The answer is 1 3/4.