Math Flashcards

Brad and Amy each have $5 for Greta's gift How much money do they have together to buy the gift?

Answer: $10

To find the total amount of money Brad and Amy have together, you simply add their individual amounts. Brad has $5 and Amy has $5, so $5 + $5 equals $10. This is a basic addition problem.

Patrice has 3 boxes of cards. Each box is 2 inches thick. The boxes are stacked on top of each other. How high is the stack?

Answer: 6 inches

To find the total height of the stack, you multiply the number of boxes by the thickness of each box. Patrice has 3 boxes, and each box is 2 inches thick, so 3 boxes multiplied by 2 inches per box equals 6 inches. This is a basic multiplication problem.

Gina is buying a shirt that costs $10.00. The sales tax is 7.5% How much will the tax be?

Answer: $ 0.75

To calculate the sales tax, you need to find 7.5% of $10.00. First, convert the percentage to a decimal by dividing by 100, which gives 0.075. Then, multiply the decimal by the original price: $10.00 * 0.075 = $0.75. Therefore, the tax will be $0.75.

Jackson Elementary will have 120 first-grade students next year. Each class can have 24 students. Using the equation 24x = 120, how many first-grade classes will the school need?

Answer: 5

The given equation, 24x = 120, represents the total number of students (120) divided by the number of students per class (24) to find the number of classes (x). To solve for x, divide both sides of the equation by 24. This calculation yields x = 5, meaning the school will need 5 first-grade classes.

The sum of the first five multiples of 6 is?

Answer: 90

First, identify the first five multiples of 6, which are 6, 12, 18, 24, and 30. Then, add these numbers together to find their sum. The sum of 6 + 12 + 18 + 24 + 30 is 90.

For a number to be divisible by 2, it must have ______ in the ones place.

Answer: 0,2,4,6,8

A number is divisible by 2 if it is an even number. Even numbers are defined as integers that can be divided by 2 without leaving a remainder. This property holds true for any number ending in 0, 2, 4, 6, or 8 in its ones place.

Which is the only number having only one factor?

Answer: 1

A factor of a number is an integer that divides the number evenly. The number 1 is unique because its only factor is itself. All other positive integers have at least two factors: 1 and the number itself (and potentially more).

Which of the following numbers is not divisible by 3?

Answer: 5482

A number is divisible by 3 if the sum of its digits is divisible by 3. For 5482, the sum of the digits is 5 + 4 + 8 + 2 = 19, and 19 is not divisible by 3. In contrast, the sums of the digits for the other options (3162 -> 12, 7956 -> 27, 8085 -> 21) are all divisible by 3.

Which of the following numbers is divisible by 8?

Answer: 10568

A number is divisible by 8 if its last three digits form a number that is divisible by 8. For 10568, the last three digits are 568. Dividing 568 by 8 gives 71, with no remainder, confirming that 10568 is divisible by 8.

Two consecutive prime numbers whose difference is 2 are called

Answer: Twin primes

Twin primes are defined as a pair of prime numbers that differ by exactly 2. Examples include (3, 5), (5, 7), and (11, 13). This specific definition distinguishes them from other types of prime number pairs.

The HCF of two consecutive number is

Answer: 1

The Highest Common Factor (HCF), also known as the Greatest Common Divisor (GCD), of two consecutive integers is always 1. This is because consecutive integers share no common factors other than 1. For example, the HCF of 4 and 5 is 1.

Which of the following is not correctly matched?

Answer: Smallest composite number - 1

The smallest composite number is 4, not 1. A composite number is a positive integer that has at least one divisor other than 1 and itself. The number 1 is neither prime nor composite, making option C incorrectly matched.

The prime factorisation of 88 is

Answer: 2 x 2 x 2 x 11

Prime factorization involves breaking down a number into its prime factors. For 88, you can repeatedly divide by 2: 88 ÷ 2 = 44, 44 ÷ 2 = 22, and 22 ÷ 2 = 11. Since 11 is a prime number, the prime factorization of 88 is 2 x 2 x 2 x 11.

How many prime numbers are there from 1 to 100?

Answer: 25

There are exactly 25 prime numbers between 1 and 100. These numbers include 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, and 97. This is a known mathematical fact.

There are 3 prime numbers between

Answer: Both A and C

To find the correct answer, we must identify which ranges contain exactly three prime numbers. The prime numbers between 40 and 50 (Option A) are 41, 43, and 47, which is three primes. The prime numbers between 50 and 60 (Option C) are 53 and 59. Therefore, only option A factually meets the condition of having three prime numbers. If 'Both A and C' is the correct answer, it implies an error in the question's premise regarding option C.

Find the LCM of 10, 15, 18.

Answer: 90

To find the Least Common Multiple (LCM) of 10, 15, and 18, we can use prime factorization. The prime factors are 10 = 2x5, 15 = 3x5, and 18 = 2x3^2. The LCM is found by taking the highest power of all prime factors present: 2^1 * 3^2 * 5^1 = 2 * 9 * 5 = 90.