STARC Trade Related
Preparation EXAM 2026
Question 1:
Solve the following expression using the correct order of operations: 4 + (15 + 10) = ?
A) 19
B) 25
C) 29
D) 50
ANSWER: C) 29
Option A (19): Incorrect. This result may come from incorrectly subtracting 10 from 15 (15 - 10 = 5) and
then adding 4, but the operation inside the parentheses should be addition.
Option B (25): Incorrect. This likely comes from adding 4 and 15 to get 19, then adding 10 to get 29.
Wait, that is the correct process. The error here is a miscalculation or misunderstanding. The correct
sum of 15 and 10 is 25, and adding 4 gives 29.
Option C (29): Correct. The order of operations dictates solving within parentheses first. 15 + 10 = 25.
Then, 4 + 25 = 29.
Option D (50): Incorrect. This could be a result of multiplying 4 by (15 + 10) which is 4 * 25 = 100, or
adding 4 to 15 to get 19, then adding 10 to get 29. This option likely comes from a complete
misapplication of the rules.
Question 2:
Evaluate the expression: (10 + 10) + 15 = ?
,A) 25
B) 30
C) 35
D) 40
ANSWER: C) 35
Option A (25): Incorrect. This ANSWER might come from adding only 10 + 15 and ignoring the first 10, or
from subtracting instead of adding.
Option B (30): Incorrect. This is the sum of the first two numbers (10 + 10 = 20) plus 10, not 15, or some
other miscalculation.
Option C (35): Correct. Following the order of operations, you solve inside the parentheses first: 10 + 10
= 20. Then, 20 + 15 = 35.
Option D (40): Incorrect. This could be a result of multiplying 10 by (10 + 15) or simply a random addition
error.
Question 3:
Does the Law of Order (Commutative Property) apply to subtraction?
A) Yes, always.
B) Yes, but only with positive numbers.
C) No.
D) Yes, if the numbers are the same.
ANSWER: C) No.
Option A (Yes, always): Incorrect. The Commutative Law states a + b = b + a. For subtraction, a - b ≠ b - a
in most cases (e.g., 5 - 3 ≠ 3 - 5).
,Option B (Yes, but only with positive numbers): Incorrect. The law does not apply to subtraction
regardless of whether the numbers are positive or negative. For example, 5 - 3 = 2, but 3 - 5 = -2.
Option C (No): Correct. The Law of Order applies only to addition and multiplication. Subtraction and
division are not commutative.
Option D (Yes, if the numbers are the same): Incorrect. While it is true that 5 - 5 = 5 - 5, this is a special
case (a - a = a - a), but the law is a general rule. This does not mean the law applies to subtraction
overall.
Question 4:
What is the result of 15 - 5 - 2 = ?
A) 12
B) 10
C) 8
D) 22
ANSWER: C) 8
Option A (12): Incorrect. This is the result of subtracting only 5 from 15 and forgetting to subtract the 2.
Option B (10): Incorrect. This is the result of subtracting 5 from 15, which is 10, but the next step is to
subtract the 2 to get 8.
Option C (8): Correct. Subtraction is performed from left to right: 15 - 5 = 10, then 10 - 2 = 8.
Option D (22): Incorrect. This would be the result of adding all the numbers together (15 + 5 + 2 = 22),
which is the opposite of the operation required.
Question 5:
, Calculate: 21 - (40 - 20) = ?
A) 41
B) 1
C) -1
D) 21
ANSWER: B) 1
Option A (41): Incorrect. This could be a result of adding 21 to 20 (40 - 20 = 20), but then forgetting to
subtract that total from the 21 (21 + 20 = 41).
Option B (1): Correct. You must solve inside the parentheses first: 40 - 20 = 20. Then, 21 - 20 = 1.
Option C (-1): Incorrect. This might come from incorrectly solving the parentheses (e.g., 20 - 40 = -20)
and then adding it to 21 (21 + (-20) = 1), or from 20 - 21 = -1.
Option D (21): Incorrect. This would be the result if you incorrectly ignore the parentheses and subtract
everything else, or it is the number given before the subtraction.
Question 6:
In a construction project, a contractor needs to order 25 pieces of rebar for one phase and 12 for the
next. If he combines the orders, how many pieces of rebar does he need in total? (Related to: Mr. Doug
has 25 boys and 12 girls)
A) 13
B) 25
C) 37
D) 47
ANSWER: C) 37
Preparation EXAM 2026
Question 1:
Solve the following expression using the correct order of operations: 4 + (15 + 10) = ?
A) 19
B) 25
C) 29
D) 50
ANSWER: C) 29
Option A (19): Incorrect. This result may come from incorrectly subtracting 10 from 15 (15 - 10 = 5) and
then adding 4, but the operation inside the parentheses should be addition.
Option B (25): Incorrect. This likely comes from adding 4 and 15 to get 19, then adding 10 to get 29.
Wait, that is the correct process. The error here is a miscalculation or misunderstanding. The correct
sum of 15 and 10 is 25, and adding 4 gives 29.
Option C (29): Correct. The order of operations dictates solving within parentheses first. 15 + 10 = 25.
Then, 4 + 25 = 29.
Option D (50): Incorrect. This could be a result of multiplying 4 by (15 + 10) which is 4 * 25 = 100, or
adding 4 to 15 to get 19, then adding 10 to get 29. This option likely comes from a complete
misapplication of the rules.
Question 2:
Evaluate the expression: (10 + 10) + 15 = ?
,A) 25
B) 30
C) 35
D) 40
ANSWER: C) 35
Option A (25): Incorrect. This ANSWER might come from adding only 10 + 15 and ignoring the first 10, or
from subtracting instead of adding.
Option B (30): Incorrect. This is the sum of the first two numbers (10 + 10 = 20) plus 10, not 15, or some
other miscalculation.
Option C (35): Correct. Following the order of operations, you solve inside the parentheses first: 10 + 10
= 20. Then, 20 + 15 = 35.
Option D (40): Incorrect. This could be a result of multiplying 10 by (10 + 15) or simply a random addition
error.
Question 3:
Does the Law of Order (Commutative Property) apply to subtraction?
A) Yes, always.
B) Yes, but only with positive numbers.
C) No.
D) Yes, if the numbers are the same.
ANSWER: C) No.
Option A (Yes, always): Incorrect. The Commutative Law states a + b = b + a. For subtraction, a - b ≠ b - a
in most cases (e.g., 5 - 3 ≠ 3 - 5).
,Option B (Yes, but only with positive numbers): Incorrect. The law does not apply to subtraction
regardless of whether the numbers are positive or negative. For example, 5 - 3 = 2, but 3 - 5 = -2.
Option C (No): Correct. The Law of Order applies only to addition and multiplication. Subtraction and
division are not commutative.
Option D (Yes, if the numbers are the same): Incorrect. While it is true that 5 - 5 = 5 - 5, this is a special
case (a - a = a - a), but the law is a general rule. This does not mean the law applies to subtraction
overall.
Question 4:
What is the result of 15 - 5 - 2 = ?
A) 12
B) 10
C) 8
D) 22
ANSWER: C) 8
Option A (12): Incorrect. This is the result of subtracting only 5 from 15 and forgetting to subtract the 2.
Option B (10): Incorrect. This is the result of subtracting 5 from 15, which is 10, but the next step is to
subtract the 2 to get 8.
Option C (8): Correct. Subtraction is performed from left to right: 15 - 5 = 10, then 10 - 2 = 8.
Option D (22): Incorrect. This would be the result of adding all the numbers together (15 + 5 + 2 = 22),
which is the opposite of the operation required.
Question 5:
, Calculate: 21 - (40 - 20) = ?
A) 41
B) 1
C) -1
D) 21
ANSWER: B) 1
Option A (41): Incorrect. This could be a result of adding 21 to 20 (40 - 20 = 20), but then forgetting to
subtract that total from the 21 (21 + 20 = 41).
Option B (1): Correct. You must solve inside the parentheses first: 40 - 20 = 20. Then, 21 - 20 = 1.
Option C (-1): Incorrect. This might come from incorrectly solving the parentheses (e.g., 20 - 40 = -20)
and then adding it to 21 (21 + (-20) = 1), or from 20 - 21 = -1.
Option D (21): Incorrect. This would be the result if you incorrectly ignore the parentheses and subtract
everything else, or it is the number given before the subtraction.
Question 6:
In a construction project, a contractor needs to order 25 pieces of rebar for one phase and 12 for the
next. If he combines the orders, how many pieces of rebar does he need in total? (Related to: Mr. Doug
has 25 boys and 12 girls)
A) 13
B) 25
C) 37
D) 47
ANSWER: C) 37
