SSAT Upper Level Math : How to subtract

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

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Example Questions

Example Question #1 : How To Subtract

\dpi{100} 4593-1296=\displaystyle \dpi{100} 4593-1296=

Possible Answers:

\dpi{100} 3497\displaystyle \dpi{100} 3497

\dpi{100} 497\displaystyle \dpi{100} 497

\dpi{100} 3397\displaystyle \dpi{100} 3397

\dpi{100} 3297\displaystyle \dpi{100} 3297

Correct answer:

\dpi{100} 3297\displaystyle \dpi{100} 3297

Explanation:

Subtract the two numbers, being careful not to forget to remove the borrowed number.

You can also add the solution back to 1296 to check your work, as addition is easier than subtraction.

\dpi{100} 1296+3297=4593\displaystyle \dpi{100} 1296+3297=4593

Example Question #22 : Number Concepts And Operations

\dpi{100} 4.8-\frac{9}{2}\displaystyle \dpi{100} 4.8-\frac{9}{2}

Possible Answers:

\dpi{100} \frac{5}{2}\displaystyle \dpi{100} \frac{5}{2}

\dpi{100} 2\displaystyle \dpi{100} 2

\dpi{100} 0.3\displaystyle \dpi{100} 0.3

\dpi{100} -5.2\displaystyle \dpi{100} -5.2

Correct answer:

\dpi{100} 0.3\displaystyle \dpi{100} 0.3

Explanation:

First convert \dpi{100} \frac{9}{2}\displaystyle \dpi{100} \frac{9}{2} into a decimal. 

\dpi{100} 9\div 2=4\ remainder\ of\ 1\displaystyle \dpi{100} 9\div 2=4\ remainder\ of\ 1

So we are left with \dpi{100} 4\frac{1}{2}\displaystyle \dpi{100} 4\frac{1}{2}, which is 4.5 in decimal form.

Now subtract:

\dpi{100} 4.8-4.5=0.3\displaystyle \dpi{100} 4.8-4.5=0.3

Example Question #2 : How To Subtract

Subtract \displaystyle \left ( 2a-3b+7c\right ) from \displaystyle \left ( 5a-4b-3c\right )

Possible Answers:

\displaystyle 7a+b+4c

\displaystyle 3a-7b+4c

\displaystyle 7a-7b+4c

\displaystyle 3a-b-10c

\displaystyle -3a+b+10c

Correct answer:

\displaystyle 3a-b-10c

Explanation:

You set up the expression with \displaystyle \left ( 5a-4b-3c\right ) on the top and \displaystyle \left ( 2a-3b+7c\right ) on the bottom. Because this is subtraction, remember to distribute the negative sign to the expression on the bottom, and then add, so

you get \displaystyle 3a-b-10c.

  

 

Example Question #3 : How To Subtract

\displaystyle K and \displaystyle L are prime integers. \displaystyle 65 < K < 75 and \displaystyle 45 < L < 55.

How many possible values of \displaystyle K - L are there?

Possible Answers:

Six

Eight

Five

Four

Seven

Correct answer:

Five

Explanation:

The prime integers between 65 and 75 are 67, 71, and 73, so \displaystyle K assumes one of those values; the prime integers between 45 and 55 are 47 and 53, so \displaystyle L assumes one of those values. Therefore, one of the following holds true:

\displaystyle K - L = 73 - 53 = 20

\displaystyle K - L = 73 - 47 = 26

\displaystyle K - L = 71 - 53 = 18

\displaystyle K - L = 71 - 47 = 24

\displaystyle K - L = 67 - 53 = 14

\displaystyle K - L = 67 - 47 = 20

There are five possible values for \displaystyle K - L (20 appears twice here).

Example Question #27 : Number Concepts And Operations

\displaystyle K and \displaystyle L are prime integers. \displaystyle 55< K < 65 and \displaystyle 85 < L < 95. What is the greatest possible value of \displaystyle L - K?

Possible Answers:

\displaystyle 34

\displaystyle 36

\displaystyle 30

\displaystyle 32

\displaystyle 28

Correct answer:

\displaystyle 30

Explanation:

The greatest possible value of \displaystyle L - K is the least possible value of \displaystyle K subtracted from the greatest possible value of \displaystyle L. The least prime between 55 and 65 is 59, and the greatest prime between 85 and 95 is 89, so \displaystyle L = 89 and \displaystyle K = 59 give the greatest possible value of \displaystyle L - K, which is equal to \displaystyle 89-59 = 30

Example Question #4 : How To Subtract

Define an operation \displaystyle \Upsilon as follows:

For all real numbers \displaystyle a, b,

\displaystyle a \Upsilon b = a^{5} - b^{4}

Evaluate: \displaystyle \frac{1}{2}\; \Upsilon\; \frac{1}{2}.

Possible Answers:

\displaystyle \frac{1}{32}

\displaystyle \frac{1}{16}

\displaystyle -\frac{1}{32}

\displaystyle -\frac{1}{16}

\displaystyle 0

Correct answer:

\displaystyle -\frac{1}{32}

Explanation:

\displaystyle a \Upsilon b = a^{5} - b^{4}

\displaystyle \frac{1}{2}\; \Upsilon\; \frac{1}{2} =\left ( \frac{1}{2} \right )^{5} - \left ( \frac {1}{2} \right )^{4}

\displaystyle = \frac{1}{32} - \frac{1}{16}

\displaystyle = \frac{1}{32} - \frac{2}{32}

\displaystyle = -\frac{1}{32}

Example Question #7 : How To Subtract

Define a function \displaystyle g as follows:

\displaystyle g(x)=\left | x^{2} - \frac{1}{x^{2}}\right |

Evaluate \displaystyle g(2) - g \left ( \frac{1}{2} \right ).

Possible Answers:

\displaystyle 7\frac{1}{2}

\displaystyle 0

\displaystyle \frac{1}{2}

\displaystyle -\frac{1}{2}

\displaystyle -7\frac{1}{2}

Correct answer:

\displaystyle 0

Explanation:

\displaystyle g(x)=\left | x^{2} - \frac{1}{x^{2}}\right |

\displaystyle g(2)=\left | 2^{2} - \frac{1}{2^{2}}\right | = \left | 4- \frac{1}{4}\right | = \left | 3 \frac{3}{4}\right |= 3 \frac{3}{4}

\displaystyle g\left ( \frac{1}{2} \right )=\left | \left ( \frac{1}{2} \right )^{2} - \frac{1}{\left ( \frac{1}{2} \right )^{2}}\right | = \left | \frac{1}{4}- \frac{1}{ \frac{1}{4}} \right | = \left | 3 \frac{3}{4}\right | = \left | \frac{1}{4}- 4 \right | = \left | - 3 \frac{3}{4} \right | = 3 \frac{3}{4}

\displaystyle g(2) - g \left ( \frac{1}{2} \right ) = 3 \frac{3}{4} - 3 \frac{3}{4} = 0

Example Question #8 : How To Subtract

Define an operation \displaystyle \forall as follows:

For all real numbers \displaystyle a ,b:

\displaystyle a \forall b = a^{4} + \frac{1}{b^{4}}.

Evaluate \displaystyle \frac{1}{2} \forall (-2 ).

Possible Answers:

The correct answer is not among the other responses.

\displaystyle \frac{1}{8}

\displaystyle -15\frac{15}{16}

\displaystyle 16\frac{1}{16}

\displaystyle 0

Correct answer:

\displaystyle \frac{1}{8}

Explanation:

\displaystyle a \forall b = a^{4} + \frac{1}{b^{4}}

\displaystyle \frac{1}{2} \forall (-2 ) = \left (\frac{1}{2} \right )^{4} + \frac{1}{(-2)^{4}}= \frac{1}{16} + \frac{1}{16} = \frac{2}{16} = \frac{1}{8}

Example Question #9 : How To Subtract

Define a function \displaystyle g as follows:

\displaystyle g(x)=\left | x^{5}-x^{2}\right |

Evaluate \displaystyle g(2) - g(-2).

Possible Answers:

\displaystyle 0

\displaystyle 60

\displaystyle -8

\displaystyle -60

\displaystyle 8

Correct answer:

\displaystyle -8

Explanation:

\displaystyle g(x)=\left | x^{5}-x^{2}\right |

\displaystyle g(2)=\left | 2^{5}-2^{2}\right | = \left | 32-4\right | = \left | 28\right | = 28

\displaystyle g(-2)=\left |( -2)^{5}-\left (-2 \right )^{2}\right | = \left | -32-4\right | = \left | -36\right | = 36

\displaystyle g(2) - g(-2) = 28 - 36 = -8

Example Question #13 : Basic Addition, Subtraction, Multiplication And Division

Define a function \displaystyle f as follows:

\displaystyle f(x) = 10 - \sqrt[3]{x} - \sqrt[5]{x}

Evaluate \displaystyle f(-1).

Possible Answers:

\displaystyle 12

\displaystyle 8

The correct answer is not among the other responses.

The expression is undefined.

\displaystyle 10

Correct answer:

\displaystyle 12

Explanation:

\displaystyle f(x) = 10 - \sqrt[3]{x} - \sqrt[5]{x}

\displaystyle f(-1) = 10 - \sqrt[3]{-1} - \sqrt[5]{-1} = 10 - (-1)- (-1)= 10+1+1 = 12

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