Estimation is great for any grade. Ask mean median range and mode with upper grades just for practice. 

Vey simple activity, that will be fun for lower level grades. Children will like telling what their favorite color is, and be able to see a graphic representation of what the favorite colors are in their class. Great start to understanding graphs.

These family math facts are helpful and can be used for multiple grade levels including 3rd, 4th, and 5th grades. I think it will be good for the students to make their own tools for learning. They will be interested in using it more if they made it themselves. 

Great for having lower grade level student recognize money and values. Start by putting all the coins in front of your student, and ask him/her to sort all pennies, nickels, dimes, quarters, and the half dollar into their own groups. Talk about value as you go.

Great for kinesthetic learners. This activity is a fun way for students to be active while learning and competing.

Perfect for showing graphically what fractions are. Can be used for other grade levels. Different objects can be used with this activity. Instead of just coloring paper squares, you could used a piece of pizza worksheet or a cake worksheet. 

Great for children learning/practicing place value. This can be used for other grade levels.Have your child tell you what number is in each place and the value of that number For example, if the number is 75, there is a 7 in the tens place and the value of that number is 7 tens or 70. Keep reading numbers aloud, but each time increase the number of digits. 

This will get your child thinking about real workd math.

This game will help students with strategy.

review basic shape terms that will be especially useful in math later on, when kids move to studying three dimensional shapes and early geometry. Great for Kinesthetic learners

Ask your student, "Was your estimate close?" and "Were there more or less pieces on the spoon than you thought?"