To the best of my current organization, these tie in with my Common Core Math Standards (K-5) chart. [More to be added.]
Counting Within 100
Operations (<, >, =, ≠, +, -, x, ÷)
Roll-the-Dice. Roll 2 dice; write the numbers in the blanks and add.
Quoits. Great practice for mental addition.
Greatest Common Factor and Least Common Denominator
Properties, Patterns, Order of Operations
Places and Rounding
Roman Numerals. Convert Super Bowl logos or figure out when movies were made from the year listed in the credits.
Borrowing from zero made easier.
Measurement & Data
Distance, Mass & Liquid Volume
Measuring Skills – liquid measurement
GallonBot – liquid measurement
Area, Perimeter, & Solid Volume
Area & Perimeter People
Legos for Perimeter and Area
Lego Butterfly Symmetry (can be made easier or more complicated)
Graphing Worksheets that make pictures (everyday, Halloween, Easter, Christmas)
Games you already own that teach math skills.
Physical Activities (Ignite) to help with math skills
Mazes, Sudoku, and other puzzles at Krazy Dad
Japanese Soroban. My boys enjoyed learning about this. There are also soroban apps.