Subtracting Mixed Numbers : āĻŽāĻŋāĻļā§ā§° āĻāĻā§āύāĻžāĻāĻļā§° āĻŦāĻŋāϝāĻŧā§āĻ
Rule 1 (āύāĻŋāϝāĻŧāĻŽ ā§§):
- If the denominators are the same, subtract the numerators and keep the denominator same. (āϝāĻĻāĻŋ āĻšā§° āĻāĻā§ āĻšāϝāĻŧ, āϤā§āύā§āϤ⧠āϞāĻŦ āĻŦāĻŋāϝāĻŧā§āĻ āĻā§°āĻŋ āĻšā§° āĻāĻā§ ā§°āĻžāĻāĻŋāĻŦ āϞāĻžāĻā§āĨ¤)
- Then subtract the whole numbers. (āϤāĻžā§° āĻĒāĻŋāĻāϤ āĻĒā§ā§°ā§āĻŖ āϏāĻāĻā§āϝāĻžāĻŦā§ā§° āĻŦāĻŋāϝāĻŧā§āĻ āĻā§°āĻŋāĻŦ āϞāĻžāĻā§āĨ¤)
- Reduce or change to a mixed number if necessary. (āĻĒā§ā§°āϝāĻŧā§āĻāύ āĻš’āϞ⧠āϏ⧰āϞ āĻŦāĻž āĻŽāĻŋāĻļā§ā§° āĻāĻā§āύāĻžāĻāĻļāϞ⧠⧰ā§āĻĒāĻžāύā§āϤ⧰ āĻā§°āĻŋāĻŦ āϞāĻžāĻā§āĨ¤)
Example | āĻāĻĻāĻžāĻšā§°āĻŖ : 4 2/4 − 2 2/4 = 2
Rule 2 (āύāĻŋāϝāĻŧāĻŽ ⧍):
- If the denominators are different, find the LCD first. (āϝāĻĻāĻŋ āĻšā§° āĻŦā§āϞā§āĻ āĻšāϝāĻŧ, āĻĒā§ā§°āĻĨāĻŽā§ LCD āĻŦāĻŋāĻāĻžā§°āĻŋāĻŦ āϞāĻžāĻā§āĨ¤)
- Change the fractions into equivalent fractions with same denominator.(āĻāĻā§āύāĻžāĻāĻļāĻŦā§ā§°āĻ āĻāĻā§ āĻšā§°āϝā§āĻā§āϤ āϏāĻŽāĻžāύ āĻāĻā§āύāĻžāĻāĻļāϞ⧠⧰ā§āĻĒāĻžāύā§āϤ⧰ āĻā§°āĻāĨ¤)
- Then subtract the numerators and keep the denominator same. (āϤāĻžā§° āĻĒāĻŋāĻāϤ āϞāĻŦ āĻŦāĻŋāϝāĻŧā§āĻ āĻā§°āĻŋ āĻšā§° āĻāĻā§ ā§°āĻžāĻāĻāĨ¤)
Example | āĻāĻĻāĻžāĻšā§°āĻŖ : 5 3/5 - 2 1/10
1st: Find LCD
• LCD of 5 and 10 is 10. (ā§Ģ āĻā§°ā§ ā§§ā§Ļ ā§° LCD āĻšā§āĻā§ ā§§ā§ĻāĨ¤)
2nd: Change fractions (āĻāĻā§āύāĻžāĻāĻļ ā§°ā§āĻĒāĻžāύā§āϤ⧰ āĻā§°āĻ) : 3/5 = 6/10
3rd: Subtract (āĻŦāĻŋāϝāĻŧā§āĻ āĻā§°āĻ) : 5 6/10 - 2 1/10 = 3 5/10
4th: Reduce (āϏ⧰āϞ āĻā§°āĻ) : 3 5/10 = 3 1/2
Soln
3/5 = 6/10
5 6/10 − 2 1/10
3 5/10
3 1/2
LCD : Lowest Common Denominator (āϏ⧰ā§āĻŦāύāĻŋāĻŽā§āύ āϏāĻžāϧāĻžā§°āĻŖ āĻšā§°))
- LCD means the smallest common multiple of two or more denominators. (LCD āĻŽāĻžāύ⧠āĻĻā§āĻāĻž āĻŦāĻž āϤāĻžāϤā§āϧāĻŋāĻ āĻšā§°ā§° āĻāĻāĻžāĻāϤāĻā§ āϏ⧰⧠āϏāĻžāϧāĻžā§°āĻŖ āĻā§āĻŖāĻŋāϤāĻāĨ¤)
- LCD is used when adding or subtracting fractions with different denominators. (āĻŦā§āϞā§āĻ āĻšā§° āĻĨāĻāĻž āĻāĻā§āύāĻžāĻāĻļ āϝā§āĻ āĻŦāĻž āĻŦāĻŋāϝāĻŧā§āĻ āĻā§°āĻžā§° āϏāĻŽāϝāĻŧāϤ LCD āĻŦā§āĻ¯ā§ąāĻšāĻžā§° āĻā§°āĻž āĻšāϝāĻŧāĨ¤)
Rule 3 (āύāĻŋāϝāĻŧāĻŽ ā§Š)
- If subtracting a mixed number from a whole number, rename the whole number as a mixed number. (āϝāĻĻāĻŋ āĻĒā§ā§°ā§āĻŖ āϏāĻāĻā§āϝāĻžā§° āĻĒā§°āĻž āĻŽāĻŋāĻļā§ā§° āĻāĻā§āύāĻžāĻāĻļ āĻŦāĻŋāϝāĻŧā§āĻ āĻā§°āĻž āĻšāϝāĻŧ, āϤā§āύā§āϤ⧠āĻĒā§ā§°ā§āĻŖ āϏāĻāĻā§āϝāĻžāĻ āĻŽāĻŋāĻļā§ā§° āĻāĻā§āύāĻžāĻāĻļ ā§°ā§āĻĒā§ āϞāĻŋāĻāĻŋāĻŦ āϞāĻžāĻā§āĨ¤)
- Regroup so the denominators become same. (regroup āĻā§°āĻŋ āĻšā§° āĻāĻā§ āĻā§°āĻŋāĻŦ āϞāĻžāĻā§āĨ¤)
Example | āĻāĻĻāĻžāĻšā§°āĻŖ
9 − 6 2/8
1st: Rename 9 (⧝ āĻ āĻĒā§āύ⧰ āϞāĻŋāĻāĻ) : 9 = 8 8/8
2nd: Subtract (āĻŦāĻŋāϝāĻŧā§āĻ āĻā§°āĻ) : 8 8/8 − 6 2/8 = 2 6/8
â3rd: Reduce (āϏ⧰āϞ āĻā§°āĻ) : 2 6/8 = 2 3/4
Ans (āĻāϤā§āϤ⧰ ) = 2 3/4