Most of the Internet resources for these early grades are found under Math Games at the right. 
Page Contents:

Broad Expectation*  Topic  Link to Applet and Description 
How good for teacher demos (13)? 
How easy for students (13)? 
How good for exploration (13)? 
Available activities 
Understand numbers, ways of representing numbers, relationships among numbers, and number systems  
Understand meanings of operations and how they relate to one another  Operations (e.g. +)  Pan Balance  Numbers or numeric expressions (e.g., 2+3 or 51) can be put on each side of the pan balance.  3 
2 
3 

Addition  Adding
with Base Ten Blocks  Use base ten blocks to represent
addition. Use the "selection marquee" (drag a rectangle)
to group up blocks. Base Blocks  base ten block introduction. 
3

2

3


Compute fluently and make reasonable estimate  
Broad Expectation*  Topic  Link to Applet and Description

How good for teacher demos
(13)?

How easy for students (13)?

How good for exploration
(13)?

Available activities

Understand patterns, relations, and functions  
Represent and analyze mathematical situations and structures using algebraic symbols  
Use mathematical models to represent and understand quantitative relationships  
Analyze change in various contexts  
Broad Expectation*  Topic  Link to Applet and Description

How good for teacher demos
(13)?

How easy for students (13)?

How good for exploration
(13)?

Available activities

Analyze characteristics and properties of two and threedimensional geometric shapes and develop mathematical arguments about geometric relationships  
Specify locations and describe spatial relationships using coordinate geometry and other representational systems  
Apply transformations and use symmetry to analyze mathematical situations  Patterns & Shapes  Pattern Blocks  Same as the physical blocks, just virtual. Nice tool. Another option.  3 
3 
3 

Use visualization, spatial reasoning, and geometric modeling to solve problems  
Broad Expectation*  Topic  Link to Applet and Description

How good for teacher demos
(13)?

How easy for students (13)?

How good for exploration
(13)?

Available activities

Understand measurable attributes of objects and the units, systems, and processes of measurement  
Apply appropriate techniques, tools, and formulas to determine measurements  Time  Judy Clock  Interactive clock. Click the circles in the upper left and right to show the time written out and digitally.  3 
3 
3 

Broad Expectation*  Topic  Link to Applet and Description

How good for teacher demos
(13)?

How easy for students (13)?

How good for exploration
(13)?

Available activities

Formulate questions that can be addressed with data and collect, organize, and display relevant data to answer them  
Select and use appropriate statistical methods to analyze data  
Develop and evaluate inferences and predictions that are based on data  
Understand and apply basic concepts of probability  
Click here for the Index for >> Online Math Games, Demonstration/Exploration Tools, and Puzzles
(This page is organized using the five content areas in school mathematics, as articulated in the NCTM Principles and Standards, 2000.)
3=Excellent for class demonstrations of mathematics
2=Fair to Good for class demonstrations of mathematics
1=Not designed for class demonstrations of mathematics
3 = No advance instruction needed (very easy to use).
2 = Short demonstration helpful (pretty easy to use).
1 = Extensive demonstration needed (hard to use without an explanation).
3=Excellent for student exploration of mathematics.
2=Fair to Good for student exploration of mathematics.
1=Not designed for student exploration of mathematics.
by: James
R. Olsen, Western Illinois University
updated:
May 24, 2012