Small quiz to repeat the basics of math for middle school. How to add or substract fractions ? 1) You must find a common denominator (thats the lower part) ! You can only add fractions with common denominators ! 2) Then you just add the numerator (the upper part) Please try this quiz in Firefox, Chome and Edge don't understand math symbols (MathML).
Both fractions already have the same denominator. Yippee. Nothing to do.
We keep the denominator and simply add the numerators: 2 quarters + 1 quarter = 3/4.
Both fractions already have the same denominator. We keep the denominator - the thirds
.
We simply subtract the numerators: 5 (thirds) - 2 (thirds) = 3 (thirds).
We need to find a common denominator (or better the least common multiple - LCM) of 3 and 6. This is 6.
You have to find the least common multiple (LCM) of 3 and 5.
Since 3 and 5 have nothing in common the LCM is the product of 3 and 5 = 15
The least common multiple of two numbers a and b is the smallest number that can be divided by both a and b giving an integer result.
24 is indeed divisible by 4 and by 6, but so is 12 and 12 is smaller.
36 is also divisible by 4 and by 6, but it is too large.
6 is not divisible by 4 as a whole.
The least common multiple of two numbers a and b is the smallest number that can be divided by both a and b giving an integer result.
24 = 2 * 12 = 2 * 2 * 6 = 2 * 2 * 2 * 3
36 = 2 * 18 = 2 * 2 * 9 = 2 * 2 * 3 * 3
LCM = 2 * 2 * 2 * 3 * 3 = 8 * 9 = 72