Exercise: Foundational Math
Questions for: Arithmetical Simplification
To evaluate a mathematical expression accurately, it is crucial to follow the correct order of operations.
Simplify the following expression: `48 รท 4 ร (7 - 3) + 5`
A: 8
B: 86
C: 53
D: 50
Answer: C
1. First, perform the operation inside the parentheses: (7 - 3) = 4.
2. The expression becomes: 48 รท 4 ร 4 + 5.
3. Next, perform division and multiplication from left to right as they have equal precedence.
4. Perform the division: 48 รท 4 = 12.
5. The expression becomes: 12 ร 4 + 5.
6. Perform the multiplication: 12 ร 4 = 48.
7. The expression becomes: 48 + 5.
8. Finally, perform the addition: 48 + 5 = 53.
Why others are wrong:
A โ This result is obtained by incorrectly performing multiplication (4 ร 4 = 16) before division when they are at the same level of precedence, leading to 48 รท 16 + 5 = 3 + 5 = 8.
B โ This result is obtained by incorrectly ignoring the parentheses and performing operations from left to right as if no parentheses were present: 48 รท 4 ร 7 - 3 + 5 = 12 ร 7 - 3 + 5 = 84 - 3 + 5 = 81 + 5 = 86.
D โ This result suggests a calculation error in the final addition (e.g., 48 + 5 = 50) or a mistake in an earlier step leading to an incorrect final sum.
A student is reviewing arithmetic operations involving fractions.
Simplify the following expression to its lowest terms: `(5/6 - 1/3) รท 1/2 + 2/3`
A: 3/7
B: 11/12
C: 5/3
D: 5/6
Answer: C
Step 1: Perform the operation inside the parentheses first.
(5/6 - 1/3) = (5/6 - 2/6) = 3/6 = 1/2
Step 2: Perform the division.
1/2 รท 1/2 = 1/2 ร 2/1 = 1
Step 3: Perform the addition.
1 + 2/3 = 3/3 + 2/3 = 5/3
Why others are wrong:
A โ Results from an incorrect order of operations, specifically performing addition before division (e.g., 1/2 รท (1/2 + 2/3)).
B โ Results from an error in fraction division, specifically multiplying the fractions instead of inverting the divisor and multiplying (e.g., 1/2 รท 1/2 incorrectly calculated as 1/2 ร 1/2 = 1/4).
D โ Results from an incorrect application of the order of operations, performing division before the operation within parentheses (e.g., 5/6 - (1/3 รท 1/2) + 2/3).
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A financial analyst is evaluating an investment portfolio. To determine a key performance indicator, they need to simplify the following expression:
What is the simplified value of the expression: (3/4)ยฒ + (1/2) ร (8/3 - 1/6)
A: 29/16
B: 11/4
C: 83/48
D: 55/48
Answer: A
1. First, calculate the term inside the parentheses: (8/3 - 1/6)
Find a common denominator, which is 6: (16/6 - 1/6) = 15/6
Simplify the fraction: 15/6 = 5/2
2. Next, calculate the exponent: (3/4)ยฒ
(3/4)ยฒ = 3ยฒ/4ยฒ = 9/16
3. Now, perform the multiplication: (1/2) ร (5/2)
(1/2) ร (5/2) = 5/4
4. Finally, perform the addition: 9/16 + 5/4
Find a common denominator, which is 16: 9/16 + (5ร4)/(4ร4) = 9/16 + 20/16
Add the fractions: (9 + 20)/16 = 29/16
Why others are wrong:
A โ Correct calculation.
B โ Incorrectly calculating (3/4)ยฒ as 3/2 instead of 9/16, leading to 3/2 + 5/4 = 6/4 + 5/4 = 11/4.
C โ Error in order of operations, specifically by calculating (1/2 ร 8/3) first, then (4/3 - 1/6), or similar misapplication of the distributive property. (e.g., (3/4)^2 + (1/2 * 8/3) - 1/6 = 9/16 + 4/3 - 1/6 = 27/48 + 64/48 - 8/48 = 83/48).
D โ Incorrectly calculating (8/3 - 1/6) as 7/6 (by subtracting numerators without finding a common denominator for the 3 and 6, or similar error), leading to 9/16 + (1/2 ร 7/6) = 9/16 + 7/12 = 27/48 + 28/48 = 55/48.
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A financial analyst is calculating a combined value involving multiple transactions.
Simplify the expression: `48 รท 6 + 2 ร 3 - 7`
A: 11
B: 0
C: 23
D: 7
Answer: D
1. Perform division: `48 รท 6 = 8`. The expression becomes `8 + 2 ร 3 - 7`.
2. Perform multiplication: `2 ร 3 = 6`. The expression becomes `8 + 6 - 7`.
3. Perform addition from left to right: `8 + 6 = 14`. The expression becomes `14 - 7`.
4. Perform subtraction: `14 - 7 = 7`.
Why others are wrong:
A โ This result is obtained by incorrectly performing addition (6+2) before division.
B โ This result is obtained by incorrectly performing subtraction (3-7) before multiplication.
C โ This result is obtained by incorrectly performing operations strictly from left to right, ignoring the hierarchy of multiplication/division over addition/subtraction.
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Scenario: A project manager is reviewing a budget calculation that includes several dependent expenses and subtractions. To verify the accuracy, they need to simplify a complex expression.
Question: Simplify the following expression: 50 - [3 * (10 + 20 / 5)] / 2
A: 41
B: 8
C: 20
D: 29
Answer: D
1. Start with the innermost operation inside the parentheses: 20 / 5 = 4.
2. Continue inside the parentheses with addition: 10 + 4 = 14.
3. Next, perform the multiplication within the square brackets: 3 * 14 = 42.
4. Perform the division outside the square brackets: 42 / 2 = 21.
5. Finally, perform the subtraction: 50 - 21 = 29.
Why others are wrong:
A โ This results from performing addition before division inside the parentheses (10 + 20) / 5 = 6.
B โ This results from forgetting to divide by 2 after simplifying the expression within the square brackets.
C โ This results from an error in the initial division (e.g., calculating 20 / 5 as 10 instead of 4).
D โ This option represents the correct simplification of the expression.
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