Looking for strong number activities to engage students of all skill levels between the grades 3–5? Or, perhaps you've got a class full of students who are just being introduced to number sense in these grade ranges. Where do you go for sound building blocks and fun activities to take your brood from novice number manipulators to advanced number sleuths? Climb aboard! The World Wide Web has an itinerary for you.

Hundreds of pages of basic math skills await you on on the World Wide Web. Begin your travels at AAA Math. Here, your students will find fun games and challenging lesson plans that offer interactive practice in such number sense topics as place value, estimation, and mental math. The site also offers an easy-to-follow explanation for every math skill.

At the math site Cut-the-Knot, students can test their number sense skills by playing the Game of Fif against their computers. The object is to be the first to select three number squares that add to 15, thus, the name Fif for fifteen. The site also offers a commentary about the mathematics that underlies the game's strategy.

Students who are looking for more math fun can visit Coolmath 4 kids. Here, young mathematicians pit their problem solving-skills against ArithMattack! and The NumberMonster! Players choose an operation and two numbers. Then they attempt to beat the clock and find an answer to the mathematical problem.

Once your students are ready to depart from numerals, they can take a crack at solving some really puzzling word problems at Math Maven's Mysteries. You will find a wide selection of engaging math stories that challenge students number sense and reading-comprehension skills. Mysteries feature other types of math skills all conveniently labeled.

Ready for some really challenging number problems? The advanced student can meet their number match at Word Problems for Kids, designed for fifth graders. A variety of fun problems increases students' number sense and computational skills. Students can also check out links that offer hints to solve the problems and check their answers against an answer key.