1.
Which number is not a multiple of 2?
Correct Answer
C. 2836
Explanation
2836 is the only number in the given options that is a multiple of 2. The other three numbers, 1845, 3907, and 1909, are not divisible by 2.
2.
Which number is a multiple of 9?
Correct Answer
D. 18,756
Explanation
18,756 is a multiple of 9 because the sum of its digits is divisible by 9. In this case, 1+8+7+5+6 = 27, and 27 is divisible by 9.
3.
Which pair of numbers is a factor pair for 28?
Correct Answer
A. 1 and 14
Explanation
The pair of numbers 1 and 14 is a factor pair for 28 because both numbers can divide evenly into 28 without leaving a remainder. When 1 is multiplied by 28, the result is 28, and when 14 is multiplied by 2, the result is also 28. Therefore, 1 and 14 are both factors of 28.
4.
Which number is a prime number?
Correct Answer
D. 47
Explanation
A prime number is a number that is only divisible by 1 and itself. In this case, only 47 fits this criteria as it is not divisible by any other number. Therefore, 47 is the prime number in the given options.
5.
Which number is not a multiple of 3?
Correct Answer
A. 2387
Explanation
A number is a multiple of 3 if the sum of its digits is divisible by 3. In the given options, the sum of the digits of 2387 is 20, which is not divisible by 3. Therefore, 2387 is not a multiple of 3.
6.
Which number is composite?
Correct Answer
B. 87
Explanation
A composite number is a positive integer that has at least one divisor other than 1 and itself. In this case, all the given numbers are prime except for 87. Therefore, 87 is the correct answer as it can be divided evenly by numbers other than 1 and itself, such as 3 and 29.
7.
Which rule is correct?
Correct Answer
C. 6: The rules of 2 and 3 must apply.
Explanation
The correct answer is 6: The rules of 2 and 3 must apply. This rule is correct because it combines the rules of both 2 and 3. The rule of 2 states that the last digit must be 1, 3, 5, 7, or 9, while the rule of 3 states that the last digit must be a multiple of 3. By combining these two rules, the rule of 6 is formed, which requires the last digit to satisfy both conditions.
8.
Select the correct statement.
Correct Answer
D. 7 is not a factor of 15.
Explanation
The statement "7 is not a factor of 15" is correct because when we divide 15 by 7, we get a remainder of 1. This means that 7 does not evenly divide into 15, making it not a factor.
9.
List all the factors of 20.
Correct Answer
C. 1, 2, 4, 5, 10 and 20
Explanation
The factors of a number are the numbers that can divide evenly into that number without leaving a remainder. In this case, the factors of 20 are 1, 2, 4, 5, 10, and 20. These numbers can all divide evenly into 20, with no remainder.
10.
Which number is not a factor of 30?
Correct Answer
B. 20
Explanation
The number 20 is not a factor of 30 because a factor of a number is a number that divides evenly into that number without leaving a remainder. In this case, 20 does not divide evenly into 30 as 30 divided by 20 equals 1 remainder 10. Therefore, 20 is not a factor of 30.
11.
Which number is a multiple of 5?
Correct Answer
D. 7460
Explanation
7460 is the only number in the given options that is divisible by 5. It ends with a 0, which means it is divisible by 10, and since 10 is a multiple of 5, 7460 is also a multiple of 5.
12.
Which number is prime?
Correct Answer
A. 53
Explanation
The number 53 is prime because it is only divisible by 1 and itself. It does not have any other factors. In contrast, the numbers 45, 98, and 64 are not prime because they have multiple factors other than 1 and themselves.
13.
Which number is not a multiple of 10?
Correct Answer
B. 7545
Explanation
The number 7545 is not a multiple of 10 because it does not end with a zero.
14.
Which number is composite?
Correct Answer
B. 93
Explanation
The number 93 is composite because it has factors other than 1 and itself. It can be divided evenly by 3 and 31, in addition to 1 and 93.
15.
Which list shows all the factors of 40?
Correct Answer
B. 1, 2, 4, 5, 8, 10, 20, 40
Explanation
The factors of a number are the numbers that can divide evenly into that number. In this case, the number is 40. To find the factors of 40, we need to determine which numbers can divide evenly into 40 without leaving a remainder. The numbers 1, 2, 4, 5, 8, 10, 20, and 40 can all divide evenly into 40, so they are all factors of 40.
16.
Which rule is not correct?
Correct Answer
B. 10: The number must end with a 0 or 5.
Explanation
The rule that states "The number must end with a 0 or 5" is not correct because it is not necessary for a number to end with 0 or 5 in order to satisfy any mathematical property or divisibility rule.
17.
Which pair of numbers is a factor pair of 50?
Correct Answer
C. 2 and 25
Explanation
The pair of numbers 2 and 25 is a factor pair of 50 because when 2 is multiplied by 25, the product is 50.
18.
Which number is a multiple of 4?
Correct Answer
B. 1836
Explanation
1836 is a multiple of 4 because it is divisible by 4 without leaving any remainder.
19.
Which number is a multiple of 3?
Correct Answer
C. 8745
Explanation
The number 8745 is a multiple of 3 because the sum of its digits (8+7+4+5) is equal to 24, which is divisible by 3.
20.
Which number is a multiple of 2?
Correct Answer
B. 29,856
Explanation
29,856 is a multiple of 2 because it is an even number. In general, a number is a multiple of 2 if it can be divided evenly by 2 without leaving a remainder. 29,856 can be divided by 2 to give 14,928, which is another whole number. Therefore, 29,856 is a multiple of 2.