Number string structure and design

How are number strings designed? Typically, people tend to describe number strings as having the following structure

Entry problem

Helper problems

Challenge problem (or clunker)


This post from Math Coach on Demand (which also has a bunch of addition and subtraction number strings) describes the structure like this:

Screen Shot 2016-03-29 at 5.27.20 PM

Again, the concept of helper problems. But is there just one “formula” for a number string? Continue reading “Number string structure and design”

Why Conjectures Matter

This post is from our colleague and friend William Deadwyler, a 6th grade math teacher and strings enthusiast who works at MS 22 (South Bronx).


This summer I met Sylvia Glauster, a 5th Grade teacher at The Ancona School in Chicago.  Sylvia led a summer institute for 5th – 8th grade teachers at Math in the City on geometry, based on a new unit she co-wrote The Architects’ Project. My work with Sylvia inspired me to start gathering and publishing students’ conjectures. Outside of my classroom is a bulletin board where conjectures are published. Some of the conjectures are right, some are wrong. All were generated in class, based on investigations and number strings that we discussed together.  Investigating these conjectures will help students develop the curiosity and persistence that all successful mathematicians share.

Continue reading “Why Conjectures Matter”