# select tools, including real objects, manipulatives, paper and pencil, and technology as appropriate, and techniques, including mental math, estimation, and number sense as appropriate, to solve problems

### Popular Tutorials in select tools, including real objects, manipulatives, paper and pencil, and technology as appropriate, and techniques, including mental math, estimation, and number sense as appropriate, to solve problems

#### What are Rates and Unit Rates?

Can you do 100 sit-ups in 2 minutes? That's a rate! Driving a car going 40 miles per hour? That's a unit rate! Watch this tutorial to learn about rate and unit rate (and the difference!).

#### How Do You Find the Probability of a Simple Event?

Working with probabilities? Check out this tutorial! You'll see how to calculate the probability of picking a certain marble out of a bag.

#### How Do You Use a Simulation to Solve a Problem?

Simulators are a great way to model an experiment without actually performing the experiment in real life. This tutorial looks at using a simulator to figure out what might happen if you randomly guessed on a true/false quiz.

#### What is Experimental Probability?

Do real life situations always work out the way your mathematical models tell you they should? No! This tutorial describes how experimental probability differs from theoretical probability.

#### What is the Distributive Property?

The distributive property is a very deep math principle that helps make math work. It's the rule that lets you expand parentheses, and so it's really critical to understand if you want to get good at simplifying expressions. So check out the tutorial and let us know what you think!

#### How Do You Figure Out the Sign of a Product or Quotient?

Multiplying and dividing numbers takes a good amount of thinking, and it's easy to make a mistake. But you can make sure that you're on the right track if you check whether the answer should be positive or negative. In this tutorial you'll see exactly how to tell if your answer will be positive or negative, even if you don't know the exact value of the answer. That way you'll always be able to check your answers!

#### What's a Rational Number?

There are lots of different kind of numbers that you should know about, and that includes rational numbers. Check out the tutorial!

#### How Do You Rewrite Subtraction as Addition?

Subtracting a positive is the same thing as adding a negative. Subtracting a negative is the same as adding a positive. Get a closer look with this tutorial!

#### How Do You Solve an Equation Using Addition?

Solving an equation for a variable? Perform the order of operations in reverse! Check it out in this tutorial.

#### What's a Percent of Change?

Lots of things in this world change their value such as cars, video games, and computers. When something either increases or decreases in value, it can be useful to know the percent of that change in value. To figure out that percent, you'll need the percent of change formula. Learn it with this tutorial!

#### What's the Formula Connecting Distance, Speed, and Time?

When you have constant speed, the same formula pops up over and over again, and that's the formula that connects distance, speed, and time. Make sure you know this formula, and if you want a refresher, check out the tutorial!

#### How Do You Find the Surface Area of a Rectangular Prism Using a Net?

Finding the surface area of a prism can be a little tricky, but a net can make the problem a little easier. Make your job easier and see how to use a net to find the surface area of a prism.

#### How Do You Solve a Two-Step Equation?

Becoming a pro at solving equations takes practice! Follow along with this tutorial to see an example of solving an equation for a variable.

#### How Do You Convert a Temperature from Fahrenheit to Celsius?

Did you know that many countries use Celsius to talk about temperature? When you have a temperature in Fahrenheit, it's helpful to know what that temperature is in Celsius. This tutorial shows you how to perform that conversion!

#### What are Equivalent Ratios?

Equivalent ratios are just like equivalent fractions. If two ratios have the same value, then they are equivalent, even though they may look very different! In this tutorial, take a look at equivalent ratios and learn how to tell if you have equivalent ratios.

#### What are Acute, Obtuse, Right, and Straight Angles?

Did you know that there are different kinds of angles? Knowing how to identify these angles is an important part of solving many problems involving angles. Check out this tutorial and learn about the different kinds of angles!

#### What are Supplementary Angles?

Knowing about supplementary angles can be very useful in solving for missing angle measurements. This tutorial introduces you to supplementary angles and shows you how to use them to solve for a missing angle measurement. Take a look!

#### How Do You Find the Area of a Composite Figure?

Composite figures are just a combination of simpler figures in disguise! In this tutorial, you'll see how to break down a composite figure into simpler figures. Then, see how to find the area of each of those individual figures to find the area of the entire composite figure. Watch the whole process in this tutorial!

#### What is a Circle?

Circles are a fundamental part of math! In this tutorial, you'll be introduced to circles and see the different parts of a circle such as the diameter, radius, and chord. Check out this tutorial to learn about circles!

#### What is Circumference?

The circumference of a circle is the distance around that circle. But what is the formula to find the circumference? In this tutorial, you'll learn the formulas for the circumference of a circle. Take a look!

#### What is the Formula for the Area of a Circle?

Did you know that you can figure out the formula for the area of a circle by first turning the circle into a parallelogram? It seems a little weird, but it really works! Watch this tutorial to see how it's done!

#### What is the Formula for the Volume of a Prism?

Trying to find the volume of a prism? Did you know that there's a formula to find that volume? In this tutorial, you'll learn about the formula for the volume of a prism. Check it out!

#### What is the Formula for the Volume of a Pyramid?

Looking for the formula for the volume of a pyramid? Then check out this tutorial! You'll learn about the formula for the volume of a pyramid and see how to use the formula in an example. Take a look!

#### What is an Unbiased Sample?

When you're trying to learn about a population, it can be helpful to look at an unbiased sample. An unbiased sample can be an accurate representation of the entire population and can help you draw conclusions about the population. This tutorial introduces you to unbiased sampling!