Subtract the fractions and write your answer in lowest terms.
four-fifths – three-eighths
(1 point)
Responses
one over forty
Image with alt text: one over forty
one and seven over forty
Image with alt text: one and seven over forty
seven over ten
Image with alt text: seven over ten
seventeen over forty
To subtract the fractions four-fifths and three-eighths, we need to find a common denominator.
The multiples of 5 are: 5, 10, 15, 20, 25, 30, 35, 40, ...
The multiples of 8 are: 8, 16, 24, 32, 40, ...
The least common multiple (LCM) of 5 and 8 is 40. So, we can rewrite the fractions with the common denominator of 40:
four-fifths = 32/40
three-eighths = 15/40
Now, we can subtract the fractions:
32/40 - 15/40 = (32 - 15)/40 = 17/40
Therefore, the answer is seventeen over forty.
If Sandy’s cookie recipe calls for one-third cup of brown sugar and she increases it by two-ninths of a cup, how much brown sugar does she use?
(1 point)
Responses
seven-ninths cup
Image with alt text: seven-ninths cup
start fraction 5 over 9 end fraction cup
Image with alt text: start fraction 5 over 9 end fraction cup
start fraction 4 over 9 end fraction cup
Image with alt text: start fraction 4 over 9 end fraction cup
one-ninth cup
To subtract the fractions four-fifths and three-eighths, we need to find a common denominator for both fractions. The least common multiple (LCM) of 5 and 8 is 40.
Now, we can convert both fractions to have a denominator of 40:
four-fifths = (4/5) * (8/8) = 32/40
three-eighths = (3/8) * (5/5) = 15/40
Subtracting the fractions, we get:
32/40 - 15/40 = 17/40
Therefore, the answer is seventeen over forty.
To subtract fractions, you need to have a common denominator. In this case, the denominators are 5 and 8. To find the least common multiple (LCM) of 5 and 8, you can use different methods like listing multiples or prime factorization.
Listing multiples:
Multiples of 5: 5, 10, 15, 20, 25, 30, 35, 40, ...
Multiples of 8: 8, 16, 24, 32, 40, 48, ...
From the list, you can see that the least common multiple of 5 and 8 is 40.
Now, you need to convert the fractions so they have the same denominator of 40. To do this, you will multiply the numerator and denominator of each fraction by the same number.
For the fraction four-fifths, you multiply both the numerator and denominator by 8 (to get a denominator of 40):
4/5 * 8/8 = 32/40
For the fraction three-eighths, you multiply both the numerator and denominator by 5 (to get a denominator of 40):
3/8 * 5/5 = 15/40
Now that both fractions have the same denominator, you can subtract the numerators:
32/40 - 15/40 = 17/40
The answer is seventeen over forty (17/40), which is the fourth option.