From the United States
Visual multiplication tool. Click a number on the horizontal and vertical axes, then the "=" button to fill in the area of the multiplication expression.
From the U.K.
Creating numbers from multiples of 1, 10, 100 using a scale:
Example: Make 251 five different ways
200 + 50 + 1
100 + 100 + 40 + 10 + 1
200 + 40 + 10 + 1
etc.
Site includes:
-Partition three-digit numbers into multiples of 100, 10 and 1 in different ways
-Partition four-digit whole numbers
-Partition numbers and decimals with up to two places
-Partition numbers and decimals with up to three places
Arithmetic videos based on Singapore Math.
Topics include:
Introduction to addition. Multiple visual ways to represent addition.
Adding a 2 digit number to a 1 digit number. Introduction to carrying.
Adding decimals
Subtraction of multi-digit numbers involving borrowing
An explanation of why (not how) borrowing/regrouping works when subtracting numbers
Subtracting decimal numbers
2 examples of multiplying a 3 digit number times a 2 digit number. 1 example of multiplying a 3 digit number times a 3 digit number.
Multiplying decimals
Dividing a two digit number into a larger number
Dividing decimal numbers
Singapore
Old School aims to be the premier resource for FREE educational material from Singapore, especially Singapore Math and Singapore Science. We have a large database of test questions and assessments and are always adding new content.
-Printable test papers
-Some tests online in English, Mathematics and Science.
-Registering on the site allows you to track your progress on the online tests (usually the "A" part of each).
-Search the questions by topic and select questions with either a multiple choice or free-response format.
Singapore
-Printable worksheets & assessments for students in grades 4,5, & 6. Some items are free, others require payment.
-Worksheets are both multiple choice and constructed response.
-Sample lessons, including model drawing with word problems from PSLE exams.
From a Singapore tutor and former teacher
Great teacher reference!
Topics include:
Addition
Subtraction
Multiplication
Division
Comparison
Fractions
Percentage
Decimals
Average
Ratio
From United States.
Activities and lessons - Math topics covered.
BASIC MATH:
Shapes & Colors, Numbers & Counting, Addition, Subtraction, Multiplication, and Division.
ADVANCED MATH:
Fractions, Decimals, Percentages, Estimation & Rounding, Ratios, and Money.
This site offers an introduction to mathematics and its variety of topics. It's not just for kids, it's for everyone (even if you aren't a number nut).