Here are a few of my favorites:

Batter's Up Baseball is a great site to practice addition and multiplication. It's especially good to use with third or fourth graders around the season opener or near World Series time. There are several features I like about this game. Students choose from attempting a single which means a basic single digit fact, a double which is a two digit number times a single digit, or a home run, which is a double digit times a doubleIn the third level digit. They choose their answer from a grid of nine choices. There is also a timer. It gives them three strikes to get it correct and score. Actually, they don't score until a run is made so it takes four singles to score a point. I had students figure out that if they did three singles and then went for a home run, they would get a grand slam. Cheering crowd sound effects add to the fun. Some of the kids wanted to stay in from recess in order to play this game. Now that's a

*hit*!

Multiflyer is a solar system themed multiplication site that was also very popular with third graders. Students must solve multiplication facts up to 12X12 in order to progress to the next planet. Students can select a difficulty level which determines the time allowed. There is also a grid which they can use to find the answer if they are stuck. If they make too many errors the game ends and they are given a report of how well they did in each times table. They can also use the practice mode for tables they find challenging.

Polygon Playground is a place where students explore polygons by using six different polygons in various sizes and colors to create patterns and pictures. Here there are no right or wrong answers, just creativity.

Fantastic Fractions is a grid of twenty five fraction activities that I put together for a class I was taking in differentiated instruction. I chose activities at different levels from basic to challenging as well as themes and types of activities. A few favorites were Fraction Flags, Fraction Monkeys, and Musical Fractions.

Star Gazing is one of the games from PBS Cyberchase, an excellent collection of challenging activities. In this game, students estimate angles in order to aim a telescope at a planet.

Play Your Cards Right is a card game for learning probability. A card is shown and you must predict whether the next card is higher or lower. At the third level, you must determine whether the odds are no chance, poor, even, good, or certain.

Possible Outcomes is another I liked for probability. It creates different combinations of hamburgers and toppings.

Chances is a dice game to illustrate probability. Once you set a number of rolls, it shows the outcome on a bar graph.

Base Block Subtraction is an activity I used with first graders near the end of the year. I visited a first grade classroom an saw them using actual base blocks to learn about regrouping so I used this site with virtual base blocks. You can vary the number of possible columns from 2 to 4 and thus change the range of problems given. When you move a ten stick to the ones column, it breaks into cubes. Subtraction is shown using both the manipulatives and the algorithm.

Fact Family Village is another activity that I created as part of a Math and Technology course. I made it to use early in second grade but it could also be beneficial in late first grade. The village is made up of streets from Zero Place to Tenth Street. Each street has houses with the fact families for that number. Clicking on the houses shows children wearing teeshirts with the various facts on them. The facts are also read aloud. I was also very aware of creating multicultural faces on the children.