How to find the lowest / least common denominator - SAT Math
Card 0 of 3
3/5 + 4/7 – 1/3 =
3/5 + 4/7 – 1/3 =
We need to find a common denominator to add and subtract these fractions. Let's do the addition first. The lowest common denominator of 5 and 7 is 5 * 7 = 35, so 3/5 + 4/7 = 21/35 + 20/35 = 41/35.
Now to the subtraction. The lowest common denominator of 35 and 3 is 35 * 3 = 105, so altogether, 3/5 + 4/7 – 1/3 = 41/35 – 1/3 = 123/105 – 35/105 = 88/105. This does not simplify and is therefore the correct answer.
We need to find a common denominator to add and subtract these fractions. Let's do the addition first. The lowest common denominator of 5 and 7 is 5 * 7 = 35, so 3/5 + 4/7 = 21/35 + 20/35 = 41/35.
Now to the subtraction. The lowest common denominator of 35 and 3 is 35 * 3 = 105, so altogether, 3/5 + 4/7 – 1/3 = 41/35 – 1/3 = 123/105 – 35/105 = 88/105. This does not simplify and is therefore the correct answer.
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What is the lowest common denominator of the fractions below?
What is the lowest common denominator of the fractions below?
In order to find the lowest common denominator, you must first list the multiples of each of the denominators of the three fractions:
The lowest common denominator between these three sets of multiples is 
.
In order to find the lowest common denominator, you must first list the multiples of each of the denominators of the three fractions:
The lowest common denominator between these three sets of multiples is
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What is the Lowest Common Denominator of 
,
and 
?
What is the Lowest Common Denominator of
The smallest number they all have in common in 
.
The smallest number they all have in common in
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