Geometry: https://www.khanacademy.org/commoncore/grade-3-G
Operations and Algebraic Thinking: https://www.khanacademy.org/commoncore/grade-3-G
Number and Operations in Base Ten: http://www.khanacademy.org/commoncore/grade-3-NBT
Number and Operations Fractions: http://www.khanacademy.org/commoncore/grade-3-NF
Measurement and Data: http://www.khanacademy.org/commoncore/grade-3-MD
Operations and Algebraic Thinking: https://www.khanacademy.org/commoncore/grade-3-G
Number and Operations in Base Ten: http://www.khanacademy.org/commoncore/grade-3-NBT
Number and Operations Fractions: http://www.khanacademy.org/commoncore/grade-3-NF
Measurement and Data: http://www.khanacademy.org/commoncore/grade-3-MD