Chapter 1
http://standards.nctm.org/document/chapter3/index.htm
This is the standards chapter in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Select Problem Solving or Algebra from the left column for across-the-grades standards. For specific grade level standards select Pre-K - 2, 3 - 5, or 6 - 8.

http://www.cut-the-knot.com/
A source of many interesting and challenging interactive games and puzzles of a problem solving nature.

http://www.cs.washington.edu/homes/jbaer/classes/blaise/blaise.html
Interactive look at number patterns in Pascal's Triangle

http://mathforum.org/workshops/usi/pascal/patterns_pascal.html
A multitude of number patterns can be found in Pascal's Triangle

http://www.computing.surrey.ac.uk/personal/ext/R.Knott/Fibonacci/fib.html
A rich and interesting source of material about Fibonacci Numbers. Start with the section, "Fibonacci Numbers and Nature."

Chapter 2
http://standards.nctm.org/document/chapter3/index.htm
This is the standards chapter in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Select Reasoning and Proof from the left column for across-the-grades standards. For specific grade level standards select Pre-K - 2, 3 - 5, or 6 - 8.

http://math.rice.edu/~lanius/Algebra/stress.html
Understanding slope and rates of change.

http://math.rice.edu/~lanius/Algebra/hottub.html
An activity to tell the story of a hot tub by looking at a graph of the water depth.

http://math.rice.edu/~lanius/Algebra/rightleft.html
Graphing right hand versus left hand proficiency.

Chapter 3
http://standards.nctm.org/document/chapter3/index.htm
This is the standards chapter in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Select Number and Operations from the left column for across-the-grades standards. For specific grade level standards select Pre-K - 2, 3 - 5, or 6 - 8.

http://www.pbs.org/teachersource/math/middle_operations.shtm
Many sources (links) that lead to topics on Number and Operation.

http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Babylonian_and_Egyptian.html
Babylonian and Egyptian mathematics with a map and photographs of ancient tablets.

Chapter 4
http://standards.nctm.org/document/chapter3/index.htm
This is the standards chapter in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Topics in Number Theory occur across several standards and different grade levels. Use Search and enter "number theory" or a particular topic in number theory to find the locations.

http://www.utm.edu/research/primes/largest.html
Up to date information about the largest prime number and other prime facts.

http://d-newton.educ.cam.ac.uk/mathsf/journalf/jan97/art1/index.html
Some interesting divisibility tests.

Chapter 5
http://standards.nctm.org/document/chapter3/index.htm
This is the standards chapter in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Select Number and Operations from the left column for across-the-grades standards. Information on Integers and Fractions can be found at grade levels 3 - 5 and 6 - 8.

http://math.rice.edu/~lanius/Lessons/Series/infinite.htm
Visualizing an infinite sum of fractions.

Chapter 6
http://standards.nctm.org/document/chapter3/index.htm
This is the standards chapter in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Select Number and Operations from the left column for across-the-grades standards. Information on Decimals and Percent can be found at grade levels 3 - 5 and 6 - 8. Use Search to find other locations for decimals and percent.

http://www.geom.umn.edu/~demo5337/Group3/hist.html
Brief history of the Pythagorean Theorem with diagrams.

Chapter 7
http://standards.nctm.org/document/chapter3/index.htm
This is the standards chapter in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Select Data Analysis and Probability from the left column for across-the-grades standards. For specific grade level standards select Pre-K - 2, 3 - 5, or 6 - 8.

http://www.pbs.org/teachersource/math.htm or

http://math.rice.edu/~lanius/Algebra/rightleft.html
Graphing right hand versus left hand proficiency.

Chapter 8
http://standards.nctm.org/document/chapter3/index.htm
This is the standards chapter in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Select Data Analysis and Probability from the left column for across-the-grades standards. For specific grade level standards select Pre-K - 2, 3 - 5, or 6 - 8.

Chapter 9
http://standards.nctm.org/document/chapter3/index.htm
This is the standards chapter in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Select Geometry from the left column for across-the-grades standards. For specific grade level standards select Pre-K - 2, 3 - 5, or 6 - 8.

http://www.pbs.org/teachersource/math/middle_geometry.shtm
An extensive list of sites relating to geometry lessons and resources for the elementary and middle school.

http://math.rice.edu/~lanius/pres/map/
History, problems, mathematics in mapmaking

http://math.rice.edu/~lanius/Geom/
Interesting geometry history, concepts, problems, and related links.

Chapter 10
http://standards.nctm.org/document/chapter3/index.htm
This is the standards chapter in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Select Measurement from the left column for across-the-grades standards. For specific grade level standards select Pre-K - 2, 3 - 5, or 6 - 8.

http://www.pbs.org/teachersource/math/middle_measurement.shtm
A list of many sites dealing with measurement activities and information.

http://physics.nist.gov/cuu/Units/index.html
Historical background and definitions of the metric system (International System of Units).

Chapter 11
http://standards.nctm.org/document/chapter3/index.htm
This is the standards chapter in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Select Geometry from the left column for across-the-grades standards. For specific grade level standards select Pre-K - 2, 3 - 5, or 6 - 8.

Miscellaneous
http://standards.nctm.org/document/index.htm
This is the Table of Contents in the Principles and Standards for School Mathematics (Standards 2000) of the National Council of Teachers of Mathematics. Start here to read or download selections of your choice.

http://www.cut-the-knot.com/
A rich source of mathematics topics, games, puzzles that encompasses all the topics in the above chapters.

http://www-groups.dcs.st-and.ac.uk/~history/BiogIndex.html
Extensive index of biographies of male and female mathematicians and scientists

http://www.pbs.org/teachersource/index.htm
Many links to math and math teaching.

http://cedar.evansville.edu/~ck6/bstud/enmc.html
Detailed biography of Emmy Noether

http://www.agnesscott.edu/lriddle/women/alpha.htm#N
Women in Mathematics site