TACHS Math : Order of operations

Study concepts, example questions & explanations for TACHS Math

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Example Questions

Example Question #1 : Order Of Operations

Evaluate:

\(\displaystyle 15 \times 8 - 12 + 25\)

Possible Answers:

\(\displaystyle 83\)

\(\displaystyle 157\)

\(\displaystyle 107\)

\(\displaystyle 133\)

Correct answer:

\(\displaystyle 133\)

Explanation:

In the order of operations, in the absence of grouping symbols, multiplication takes precedence over addition and subtraction. Multiply 15 by 8 first:

\(\displaystyle 15 \times 8 - 12 + 25\)

\(\displaystyle =120 - 12 + 25\)

Addition and subtraction have equal precedence and are worked in left-to-right order. Subtract 120 and 12 next:

\(\displaystyle =108 + 25\)

Now add:

\(\displaystyle = 133\)

Example Question #1 : Order Of Operations

What is the value of \(\displaystyle (3+1)^2\times 2-(2\times2)+15\)?

Possible Answers:

\(\displaystyle 51\)

\(\displaystyle 22\)

\(\displaystyle 39\)

\(\displaystyle 43\)

Correct answer:

\(\displaystyle 43\)

Explanation:

Make sure to follow the order of operations. 

Start by simplifying what is found in the parentheses.

\(\displaystyle (3+1)^2\times 2-(2\times2)+15=4^2\times 2-4+15\)

Next, simplify any exponents.

\(\displaystyle 4^2\times 2-4+15=16 \times 2-4+15\)

Next, simplify any multiplication and division.

\(\displaystyle 16 \times 2-4+15=32-4+15\)

Finally, simplify any addition and subtraction.

\(\displaystyle 32-4+15=43\)

Example Question #21 : Tachs: Math And Ability

What is the value of \(\displaystyle 3+(7\times 4)\times (2+1)-10\)?

Possible Answers:

\(\displaystyle 81\)

\(\displaystyle 65\)

\(\displaystyle 91\)

\(\displaystyle 77\)

Correct answer:

\(\displaystyle 77\)

Explanation:

Make sure you follow the order of operations (PEMDAS: parentheses, exponents, multiplication, division, addition, and subtraction—from the left to the right).

Start by simplifying what's found within the parentheses:

\(\displaystyle 3+(7\times 4)\times (2+1)-10=3+28 \times 3-10\)

Next, simplify any multiplication and division.

\(\displaystyle 3+28 \times 3-10=3+84-10\)

Finally, simplify any addition and subtraction.

\(\displaystyle 3+84-10=77\)

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