Comparing Fractions

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ISEE Lower Level: Quantitative Reasoning › Comparing Fractions

Questions 1 - 10
1

A group of 24 students went on a field trip. One-third (\(\frac{1}{3}\)) of the students chose to visit the dinosaur exhibit. Three-eighths (\(\frac{3}{8}\)) of the students chose the space exhibit. Which exhibit was chosen by more students?

An equal number of students chose each exhibit.

The dinosaur exhibit

There is not enough information to tell.

The space exhibit

Explanation

To solve this, we must compare the fractions \(\frac{1}{3}\) and \(\frac{3}{8}\). The total number of students, 24, is extra information. To compare the fractions directly, we find a common denominator, which is 24. Dinosaur exhibit: \(\frac{1}{3} = \frac{8}{24}\). Space exhibit: \(\frac{3}{8} = \frac{9}{24}\). Since \(9 > 8\), \(\frac{9}{24} > \frac{8}{24}\), which means a larger fraction of students chose the space exhibit. Therefore, the space exhibit was chosen by more students.

2

On Monday, Chloe ate \(\frac{1}{2}\) of a small pizza. On Tuesday, she ate \(\frac{1}{3}\) of a large pizza. Which of the following must be true about the amount of pizza Chloe ate?

Chloe ate the same amount of pizza on both days.

Chloe ate more pizza on Monday.

Chloe ate more pizza on Tuesday.

It cannot be determined who ate more pizza.

Explanation

The fractions refer to different-sized wholes (a 'small pizza' versus a 'large pizza'). Because the total sizes of the pizzas are not the same and are not specified, we cannot compare the absolute amounts of pizza eaten. For example, \(\frac{1}{3}\) of a very large pizza could be more than \(\frac{1}{2}\) of a very small pizza. Without more information about the sizes of the pizzas, no definitive comparison can be made.

3

Three ropes have lengths of \(\frac{5}{9}\) meter, \(\frac{1}{2}\) meter, and \(\frac{4}{7}\) meter. Which rope's length is between the lengths of the other two?

The \(\frac{1}{2}\) meter rope

The \(\frac{4}{7}\) meter rope

The \(\frac{5}{9}\) meter rope

All the ropes must be the same length.

Explanation

To find the rope with the middle length, we must order the fractions \(\frac{5}{9}\), \(\frac{1}{2}\), and \(\frac{4}{7}\). One way is to convert them to decimals: \(\frac{1}{2} = 0.5\), \(\frac{5}{9} = 0.555...\), and \(\frac{4}{7} \approx 0.571\). Ordering these from least to greatest gives 0.5, 0.555..., 0.571. This corresponds to the order \(\frac{1}{2}\), \(\frac{5}{9}\), \(\frac{4}{7}\). The fraction in the middle is \(\frac{5}{9}\).

4

In a school election for class president, Candidate A received \( \frac{9}{10} \) of the votes in Mr. Smith's class. In Ms. Jones's class of the same size, Candidate B received \( \frac{13}{15} \) of the votes. Which statement correctly compares the results?

Candidate A received \(\frac{4}{5}\) fewer votes than Candidate B.

Candidate A received a greater fraction of the votes.

Candidate B received a greater fraction of the votes.

Both candidates received the same fraction of the votes.

Explanation

To compare \(\frac{9}{10}\) and \(\frac{13}{15}\), we can find a common denominator, which is 30. Convert the fractions: Candidate A: \(\frac{9}{10} = \frac{27}{30}\). Candidate B: \(\frac{13}{15} = \frac{26}{30}\). Since \(27 > 26\), we know that \(\frac{27}{30} > \frac{26}{30}\). Therefore, Candidate A received a greater fraction of the votes.

5

Which of the following fractions is closest in value to \(\frac{1}{2}\)?

\( \frac{5}{9} \)

\( \frac{7}{12} \)

\( \frac{3}{8} \)

\( \frac{4}{7} \)

Explanation

To find which fraction is closest to \(\frac{1}{2}\), we find the absolute difference between each fraction and \(\frac{1}{2}\). A) \(|\frac{3}{8} - \frac{4}{8}| = \frac{1}{8}\). B) \(|\frac{4}{7} - \frac{1}{2}| = |\frac{8}{14} - \frac{7}{14}| = \frac{1}{14}\). C) \(|\frac{5}{9} - \frac{1}{2}| = |\frac{10}{18} - \frac{9}{18}| = \frac{1}{18}\). D) \(|\frac{7}{12} - \frac{1}{2}| = |\frac{7}{12} - \frac{6}{12}| = \frac{1}{12}\). Now we must find the smallest of these differences: \(\frac{1}{8}, \frac{1}{14}, \frac{1}{18}, \frac{1}{12}\). When fractions have the same numerator (1 in this case), the one with the largest denominator is the smallest. The largest denominator is 18, so \(\frac{1}{18}\) is the smallest difference. Therefore, \(\frac{5}{9}\) is closest to \(\frac{1}{2}\).

6

Marco ate \( \frac{2}{5} \) of his pizza. Jada ate \( \frac{3}{8} \) of her pizza, which was the same size as Marco's. Who has more pizza left over?

They have the same amount of pizza left over.

Marco has more pizza left over.

Jada has more pizza left over.

There is not enough information to determine who has more left.

Explanation

First, determine the fraction of pizza each person has left. Marco has \(1 - \frac{2}{5} = \frac{3}{5}\) of his pizza left. Jada has \(1 - \frac{3}{8} = \frac{5}{8}\) of her pizza left. Next, compare these two fractions. To compare \(\frac{3}{5}\) and \(\frac{5}{8}\), find a common denominator, which is 40. Marco's remaining pizza is \(\frac{3}{5} = \frac{24}{40}\). Jada's remaining pizza is \(\frac{5}{8} = \frac{25}{40}\). Since \(\frac{25}{40} > \frac{24}{40}\), Jada has more pizza left over.

7

A recipe calls for an amount of sugar that is more than \( \frac{1}{3} \) cup but less than \( \frac{1}{2} \) cup. Which of the following amounts of sugar could be used?

\( \frac{5}{12} \) cup

\( \frac{2}{3} \) cup

\( \frac{3}{5} \) cup

\( \frac{1}{4} \) cup

Explanation

To find a fraction between \(\frac{1}{3}\) and \(\frac{1}{2}\), convert them to fractions with a common denominator. A common denominator for all the fractions is 60. \(\frac{1}{3} = \frac{20}{60}\) and \(\frac{1}{2} = \frac{30}{60}\). We need a fraction between \(\frac{20}{60}\) and \(\frac{30}{60}\). Let's convert the answer choices: A) \(\frac{1}{4} = \frac{15}{60}\) (too small). B) \(\frac{5}{12} = \frac{25}{60}\) (this is between \(\frac{20}{60}\) and \(\frac{30}{60}\)). C) \(\frac{2}{3} = \frac{40}{60}\) (too large). D) \(\frac{3}{5} = \frac{36}{60}\) (too large). Therefore, \(\frac{5}{12}\) is the correct amount.

8

Four friends are painting a long fence. After one hour, Liam has painted \( \frac{3}{4} \) of his section, Noah has painted \( \frac{2}{3} \) of his section, Olivia has painted \( \frac{5}{6} \) of her section, and Emma has painted \( \frac{7}{12} \) of her section. All sections are the same size. Who is in the lead, having painted the most?

Liam

Noah

Olivia

Emma

Explanation

To determine who is in the lead, we must find the largest fraction among \(\frac{3}{4}\), \(\frac{2}{3}\), \(\frac{5}{6}\), and \(\frac{7}{12}\). A common denominator for these fractions is 12. Convert each fraction: Liam: \(\frac{3}{4} = \frac{9}{12}\). Noah: \(\frac{2}{3} = \frac{8}{12}\). Olivia: \(\frac{5}{6} = \frac{10}{12}\). Emma: \(\frac{7}{12}\). Comparing the numerators, 10 is the largest. Therefore, Olivia has painted the most and is in the lead.

9

Which of the following expressions results in the largest value?

\( \frac{1}{3} + \frac{1}{12} \)

\( \frac{1}{2} - \frac{1}{10} \)

\( \frac{3}{4} - \frac{1}{2} \)

\( \frac{1}{5} + \frac{1}{20} \)

Explanation

When comparing fractions through addition and subtraction, you need to find common denominators and calculate the actual values to determine which expression yields the largest result.

Let's work through each expression systematically. For choice A: $$\frac{1}{2} - \frac{1}{10}$$, convert to the common denominator 10: $$\frac{5}{10} - \frac{1}{10} = \frac{4}{10} = 0.4$$

For choice B: $$\frac{1}{5} + \frac{1}{20}$$, convert to the common denominator 20: $$\frac{4}{20} + \frac{1}{20} = \frac{5}{20} = 0.25$$

For choice C: $$\frac{3}{4} - \frac{1}{2}$$, convert to the common denominator 4: $$\frac{3}{4} - \frac{2}{4} = \frac{1}{4} = 0.25$$

For choice D: $$\frac{1}{3} + \frac{1}{12}$$, convert to the common denominator 12: $$\frac{4}{12} + \frac{1}{12} = \frac{5}{12} ≈ 0.417$$

Comparing the results: A gives 0.4, B gives 0.25, C gives 0.25, and D gives approximately 0.417. Choice D produces the largest value.

Choice A is close but falls short of D's value. Choices B and C both equal 0.25, making them tied for the smallest values. The key trap here is that addition doesn't automatically create larger results than subtraction—the actual fractional values matter more than the operations.

When comparing fraction expressions, always calculate the final decimal values rather than making assumptions based on whether you're adding or subtracting. Convert everything to a common form for easy comparison.

10

A water tank was \(\frac{4}{5}\) full. After a day of use, it was \(\frac{1}{3}\) full. A different, identical tank was \(\frac{5}{6}\) full and after a day was \(\frac{1}{2}\) full. Which tank had a greater fraction of its water used?

It is not possible to determine from the information given.

The first tank

Both tanks had the same fraction of water used.

The second tank

Explanation

First, calculate the fraction of water used from each tank. For the first tank, the amount used is \(\frac{4}{5} - \frac{1}{3}\). The common denominator is 15: \(\frac{12}{15} - \frac{5}{15} = \frac{7}{15}\). For the second tank, the amount used is \(\frac{5}{6} - \frac{1}{2}\). The common denominator is 6: \(\frac{5}{6} - \frac{3}{6} = \frac{2}{6} = \frac{1}{3}\). Now, compare the fractions of water used: \(\frac{7}{15}\) and \(\frac{1}{3}\). The common denominator is 15: \(\frac{1}{3} = \frac{5}{15}\). Since \(\frac{7}{15} > \frac{5}{15}\), the first tank had a greater fraction of its water used.

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