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A prime number is one that only has two factors: one and itself. This means that the number can’t be divided evenly by any number but one.

Prime numbers are the building blocks of numbers. You can break down all numbers to prime numbers. There are an infinite number of prime numbers, but they are less frequent as numbers get larger. For these reasons, mathematicians have enjoyed studying and discovering other prime numbers.

So how do you find prime numbers? Let’s look at the numbers up to 100. As Eratosthenes discovered, there are a few multiples that you can look for to weed out the numbers that are not prime numbers. Start with a chart up to 100:

First, cross out the numbers that are multiples of 2 (hold off on 2):

Then, skip 5 but remove the rest of the multiples of 5:

Next, cross out the multiples of 3 starting with 6:

And finally, locate the multiples of 7 (not including 7). Go ahead and cross those out, too:

Now, look at the numbers that are left. These are the prime numbers to 100. Those 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.

If you continue to test for prime numbers beyond 100, see if you can evenly divide the number into groups.

If a number isn’t a prime number, it’s probably going to be a composite number. Composite numbers are simply ones that have more than 2 factors. For example, the factors of 4 include 1 x 4 and 2 x 2. Since there are more factors than just one and itself, 4 would be considered a composite number (even if it has only 3 factors: 1, 2, and 4).

Years ago, mathematicians classified zero and one as prime numbers. However, now these numbers aren’t considered to be prime or composite numbers. To be a prime number, a number should have just 2 factors: 1 and itself. However, 1 = 1 x 1. Therefore, 1 only has 1 factor: itself. Therefore, it can’t be a prime or a composite number.

Zero acts in the same way: 0 = 0 x 0. Because it only has 1 factor, 0 is also difficult to classify as either a prime or composite number.

As you study numbers, start by classifying whether each number is a prime or composite number. If it’s a composite number, try to break it down to its prime number factors. Soon, you’ll become a pro with prime numbers. So, when someone asks “what are prime numbers?” you can teach them all about it!

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]]>Help your child understand the importance of learning math for the real-world. Your child may struggle with figuring out measurements on a worksheet, but cooking doesn’t feel like work and yields delicious results!

Have your child join you as you calculate prices at the grocery store. For instance, ask them how much 3 gallons of milk will cost if it costs $2 per gallon? Practice fractions with a pie or a quarter pound cheeseburger, or measure items around the house. Make the work hands-on so your child understands how to use math outside of the classroom.

You can find simple math games online to help your child master various concepts. Or, make your own. A simple one that you could play in the car involves choosing a number. Then, take turns saying multiplication pairs that equal the number you chose.

Think about ways to practice the math concepts your child is struggling with as you’re on the road, waiting in line, or hanging out at home. Make it fun, so your child can practice in a stress-free way.

Word problems often confuse young students. It can be difficult to determine what the problem is asking them to do. Help your child practice these at home. You can find grade-appropriate examples online. Then, have your child read the problem out loud. This is a great way to help your child slow down, and you can find out what your child is struggling to understand.

Work together to determine what the problem requires. In the process, you can model your thinking about it for your child. As your child gets more and more confident, make sure to help less and less. However, you could ask leading questions to help your child when he or she gets stuck.

One of the most important things about 3rd grade math is learning how to think. By the end of 3rd grade, the expectation is that your child will be able to think and reason out a problem to find the solution. To help your child learn to talk about math and explain solutions, it can be helpful to have your child take the reins as the teacher. Play school with your child as the teacher. Have your child explain a topic to you. You could even get a problem wrong, so your child can explain how to find the correct answer next time.

Whether you’re driving to grandma’s or spending time at home, you can also use a tablet or computer for math apps and websites. Find ones that offer practice with concepts that your child needs to review. There are lots of fun ones available that will engage your child and provide the practice needed to master the concepts.

If you’re unsure where to start as you work with your child, don’t hesitate to reach out to your child’s teacher. Find out how your child is doing and what resources may be available for you to help. Partnering with your child’s teacher is a great way to know more about your child’s level and what you can do to help your child get where he or she needs to be. Then, find methods that work with your child to practice and master the concepts in 3rd grade math.

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