Race to double numbers in this competitive card game. Try one-digit or two-digit numbers, or more!

This two-ingredient dough, sometimes called "moon sand," is a quick and cheap way to let kids explore their senses, build fine motor skills, and play.

Challenge your high school student to find the flaw in this short mathematical proof that one is equal to two.

Does your child need counting help? Here's a simple game that kids can do at home to help them practice counting to two-digit numbers.

In this cool science experiment, learn about magnetism and poles, and test magnet strength to find out if two magnets are twice as strong as one.

Create homemade seed packets with your kids. This activity combines your kids' love of science and the outdoors with a little writing and drawing fun.

Sharing can be a challenge, and division doubly so! Practice halving numbers in this competitive card game.

Engage your third-grader in this version of the classic game and she will get lots of practice using mental math to solve addition and subtraction problems.

This game reinforces the meaning of the term "multiples" and is fast enough to hold the attention of your fourth-grader.

This variation of Duck, Duck, Goose is played in pairs, which means a lot more activity for participants!

This project compares the strength of one, two, and three-ply toilet paper.

In this project, you will observe and record changes in sunspots over two weeks.

Young artists will combine two animals into one in this imaginative art-project-slash-game!

Coil your daughter's two favorite colors into a wearable pendant with just a few scraps of felt!

Transform a single sheet of card stock into a double-sided painting of opposites: on one side, a bright daytime landscape, on the other, a dusky evening scene.

Drift away with this charming craft that lets your child create a paper hot air balloon or two.

Determine whether a hot liquid cools off faster when liquid is added before or after a two minute wait.

Help your first grade child figure out contractions and their original two words by playing this simple game, Contraction Concentration!

All your preschooler needs to create a personalized Halloween memento is their two hands and some black paint.

In this science fair project, young children discover what happens when two fluids that have different densities get together.

In this activity, your child will experience multitasking, then mindfulness and compare the two in terms of productivity and calmness.

Is it solid or liquid? Create oobleck and witness the amazingly weird oscillation between the two!

Introduce your fifth grader to the Kinara, part of the Kwanzaa tradition, by playing this fast-paced, two player game!

Did you ever drink spoiled milk? Find out whether whole milk spoils at the same rate as 2% and skim milk.

Teach your little scientist about the amazing powers of gravity by comparing the falling speeds of two yummy fruits

Want to reinforce new middle school math terms (variables, equations), while helping your child solve simple one and two-step equations?

This science fair project idea focuses on two classes of sugars monosaccharides (fructose) and disaccharides (sucrose or table sugar).

In this experiment, your child will create two compost bins and see if he can determine what attracts fruit flies.

Administer IQ tests to volunteers. have one group practice typical IQ test problems. Then compare results of the two groups.

Use two toilet paper rolls to make a pair of homemade binoculars and let the games begin. Here's how: