We live in a world written in number, from the binary code that drives the information age to the dollar, euro and yuan figures that shape the behavior of nations, corporations and individuals. For ...

Add and subtract within 100 using compose, decompose, and place value strategies. Engage with a number talk to sum near-doubles using compensation. Add and subtract within 100 in more than one way.

A long-standing puzzle seems to constrain how addition and multiplication relate to each other. A graduate student has gone further than anyone else in establishing the connection. In 1983 the ...