SSAT Upper Level Math : How to add complex fractions

Study concepts, example questions & explanations for SSAT Upper Level Math

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Example Questions

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Example Question #63 :Rational Numbers

Add:

Possible Answers:

Correct answer:

Explanation:

First, add the fractions found in the numerator and denominator of the complex fraction. To add two fractions, they need to have a common denominator. You can create a common denominator by multiplying the numerator and denominator of one fraction byas a fraction made up of the denominator of the other fraction. For example, if you need to create a common denominator forand, you would multiplybyandby. Since this just multiplies each fraction by, it doesn't change the fractions' values, just the way in which they are represented.

Now, divide those two fractions.

Finally, add:

Example Question #64 :Rational Numbers

Solve.

Possible Answers:

Correct answer:

Explanation:

Find the least common denominator between the two fractions. In our case bothandgo intothus, this is our common denominator.

The top is multiplied by 2x for the left fraction and to get:

.

For the right fraction, the top is multiplied by 7.

To solve we need to add these two fractions together.

Final answer should read,

.

Example Question #65 :Rational Numbers

Solve.

Possible Answers:

Correct answer:

Explanation:

By inspection, the denominator of the left fraction is a perfect square. Since the right fraction already has a, just multiply top and bottom byso the denominators of both fraction are the same.

The top should readwith a bottom of.

After simplification, the answer is revealed.

Example Question #66 :Rational Numbers

Simplify.

Possible Answers:

Correct answer:

Explanation:

If you can recognize thatis -1 then the answer is quick.

Otherwise just find the least common denominator which is.

The numerator of the new fraction will be. It may be tempting to thinkshould have been the right answer, however, the question does say simplify and yes this can be simplified. If you factor theout of the numerator, it's. The bottom does look very similar to the top only the signs are flipped. This means if you factor out aon the bottom, the quadratic equation should match and cancel out leaving you with the answer of.

Example Question #67 :Rational Numbers

Solve.

Possible Answers:

Correct answer:

Explanation:

First focus on the big fraction specificall,y the numerator. We need to find a common denominator in the numerator in order to add the two fractions and simplify the expression.

The top should have a common denominator of.

Therefore the top should become.

Now lets look at the denominator of the big fraction. We again need to find a common denominator for the two components. In this case it will be.

Therefore the bottom should become.

Since we need to have a single fraction added to a, we need to multiply top and bottom byso we can add the fractions easier.

So far, the new equation to solve is.

Same thing, find the least common denominator and solve to arrive at the final answer.

Example Question #68 :Rational Numbers

Solve.

Possible Answers:

Correct answer:

Explanation:

Although intimidating, just focus on the inner fraction and work your way up.

Common denominator isso that should lead to

.

By multiplying everything bythis should lead to.

Common denominator is nowand this should arrive at,

which is the final answer when everything is simplified.

Example Question #69 :Rational Numbers

Simplify.

Possible Answers:

Correct answer:

Explanation:

Work on each fraction and start from the bottom and work your way up.

For the left fraction, it should be

sinceis the common denominator.

Then multiply by the inverse to get.

For the right, it's the same concept as the final fraction to get is.

Finally find the common denominator of these new complex fractions and solve to get the final answer.

Example Question #70 :Rational Numbers

Simplify.

Possible Answers:

Correct answer:

Explanation:

By careful inspection, the fractions all reduce to.

All the fractions have values in the numerator and denominator that cancel out.

There are five of these so multiplybyto get the final answer.

Answer should be.

Example Question #71 :Rational Numbers

Simplify.

Possible Answers:

Correct answer:

Explanation:

Don't try to find the least common denominator as it will take a lot of time and a definite mistake in arithmetic. Instead try to see if these quadratics can simplify.

Upon inspection, we get

.

Remember, to break down the quadratic equation by finding the binomials, two numbers that are factors of c must add up to make b.

With the cancellations, we should get

.

The common denominator will be

Remember when foiling, you multiply the numbers/variables that first appear in each binomial, followed by multiplying the outer most numbers/variables, then multiplying the inner most numbers/variables and finally multiplying the last numbers/variables. The left fraction numerator is multiplied byand the right fraction numerator is multiplied by.

总的来说,新fraction should read

.

After simplification, answer should be.

Example Question #72 :Rational Numbers

Simplify.

Possible Answers:

None of the above are correct.

Correct answer:

Explanation:

Try to simplify the fraction rather than finding the least common denominator. By breaking the quadratic equation into its factors, it becomes:

.

Remember, to break down the quadratic equation by finding the binomials, two numbers that are factors of c must add up to make b. Also, if the values of a, b, and c in the quadratic equation can be reduced, then factor out that divisor to make the quadratic easier to factor.

Upon cancelling, we should get

.

The common denominator isoror.Remember when foiling, you multiply the numbers/variables that first appear in each binomial, followed by multiplying the outer most numbers/variables, then multiplying the inner most numbers/variables and finally multiplying the last numbers/variables. Then multiply the numerator of left fraction byand the numerator of right fraction byand the new fraction should look like,

.

Upon distributing the four and simplifying the fraction, answer is shown.

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