The new Carnival of Mathematics is up and running at Modulo Errors. Highlights for me included:

Teaching Math

One opinion about when to introduce formal arithmetic (workbooky math) to children. What is the opportunity cost of too-early mathematics?

Criss-Cross Multiplication

An algorithm for two-digit multiplication that is easier for mental math.

Party For Polyglots

A brain teaser puzzle, not too difficult.

Coloring Knots

A topological doodling project.

Oops, sorry about the missing link; I was trying to link both the sites and the articles but mangled yours: it’s fixed now!