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Question

Evaluate: (13 × 8 - √81 × 6 + 1 ) ÷ (√49 + 72 - 18 × 2 + 19)

The correct answer is

51/62

Evaluate the Mathematical Expression Using BODMAS/PEMDAS

To evaluate the given expression, we need to follow the order of operations, often remembered by acronyms like BODMAS or PEMDAS.

  • Brackets (or Parentheses)
  • Orders (or Exponents, roots)
  • Division and Multiplication (from left to right)
  • Addition and Subtraction (from left to right)

The given expression is:

\((13 \times 8 - \sqrt{81} \times 6 + 1 ) \div (\sqrt{49} + 72 - 18 \times 2 + 19)\)

We will evaluate the numerator and the denominator separately.

Evaluating the Numerator: \(13 \times 8 - \sqrt{81} \times 6 + 1\)

First, calculate the square root:

  • \(\sqrt{81} = 9\)

Substitute this value back into the numerator expression:

\(13 \times 8 - 9 \times 6 + 1\)

Next, perform the multiplications from left to right:

  • \(13 \times 8 = 104\)
  • \(9 \times 6 = 54\)

Substitute these values back:

\(104 - 54 + 1\)

Finally, perform addition and subtraction from left to right:

  • \(104 - 54 = 50\)
  • \(50 + 1 = 51\)

So, the value of the numerator is 51.

Evaluating the Denominator: \(\sqrt{49} + 72 - 18 \times 2 + 19\)

First, calculate the square root:

  • \(\sqrt{49} = 7\)

Substitute this value back into the denominator expression:

\(7 + 72 - 18 \times 2 + 19\)

Next, perform the multiplication:

  • \(18 \times 2 = 36\)

Substitute this value back:

\(7 + 72 - 36 + 19\)

Finally, perform addition and subtraction from left to right:

  • \(7 + 72 = 79\)
  • \(79 - 36 = 43\)
  • \(43 + 19 = 62\)

So, the value of the denominator is 62.

Performing the Final Division

Now, divide the numerator by the denominator:

\(\frac{\text{Numerator}}{\text{Denominator}} = \frac{51}{62}\)

The result of the evaluation is \(\frac{51}{62}\).

Revision Table: Order of Operations (BODMAS/PEMDAS)

Order Operation Type Example
1 Brackets/Parentheses \( (2+3) \times 4 \)
2 Orders/Exponents/Roots \( 5^2 \) or \( \sqrt{16} \)
3 Division and Multiplication (Left to Right) \( 10 \div 2 \times 3 \)
4 Addition and Subtraction (Left to Right) \( 8 - 3 + 5 \)

Additional Information: Understanding Arithmetic Operations and Square Roots

This problem combines basic arithmetic operations (addition, subtraction, multiplication, division) with square roots.

  • Arithmetic Operations: These are the four fundamental ways to combine numbers. Following the correct order is crucial for getting the right answer in complex expressions.
  • Square Root: The square root of a number is a value that, when multiplied by itself, gives the original number. For example, the square root of 81 (\(\sqrt{81}\)) is 9 because \(9 \times 9 = 81\). Similarly, the square root of 49 (\(\sqrt{49}\)) is 7 because \(7 \times 7 = 49\).
  • Expressions: A mathematical expression is a combination of numbers, variables, and operation symbols. Evaluating an expression means finding its numerical value.

Always break down complex expressions into smaller, manageable steps following the BODMAS/PEMDAS rule to avoid errors.

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Important Questions from Bodmas Rule

  1. If 2945 ÷ 19 – 11 × 5 = 29 + a, find the value of a.

  2. DIRECTIONS: What should come in place of the question mark (?) in the following question?

    3800 - 22 × 1968 ÷ 48 = ? × 7

  3. Solve: {7.88 × 2 + 2.4 × 5 - 242.4 ÷ 4 + [9.2 × 4 - 2.46 of 3 + (36.3 ÷ 3 - 1.42 × 2)]} 

  4. What will come in the place of question mark (?) in the given expression?

    (420 ÷ 12 × 35 + 452- 152) = ?2

  5. What will come in the place of the question mark ‘?’ in the following question?

    4/5 ÷ 2/15 of (2/3 + 4/21) - (7/4 - 4/3) = ?

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