About Kathy: Kathy Minas is a 5th grade teacher at a public school in Los Angeles. She is an enthusiastic mathematician … More

# Category: multiplication strings

# Prime Climb Number String

Last month, I worked in Andrew Eller’s amazing 4th grade classroom in Los Angeles that was beginning an exploration of … More

# Trusting the digits: Developing place value understanding

For several years, across various school communities, a teacher will tell me, “My kids don’t really have a strategy for … More

# 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 … More

# Cars, coffee, and climbing stairs: Inviting students into the story

Here’s another important contribution from our friend and colleague Marcelle Good — a 6th grade teacher at School of the … More

# Video: Division on the open number line in fourth grade

# What is the difference between Number Strings and Number Talks?

What’s the difference between a Number String and a Number Talk?

# Beyond Skip Counting

This post comes to us from strings enthusiast and middle school teacher Marcelle Good, who works at School of the … More

# Chocolate Arrays

Lately, I’ve been seeing arrays everywhere I go: at the grocery store, at the pharmacy, at the farmers’ market. And, … More

# The delight of disequilibrium

Disequilibrium is Piaget’s term to describe when what a learner already knows comes into conflict with new information. Learners must … More

# Searching for Friendly Numbers

Students who are working to become efficient with fractions must learn to seek out “friendly” numbers — a shifting target … More

# From additive to multiplicative thinking

A few weeks ago our colleague and collaborator Pam Weber Harris led a really interesting numeracy workshop at Math in … More

# Challenge problems, helper problems

When designing strings, there are typically one or more helper problems before a challenge problem. For example, you might start … More

# Arrays on the West Side

We recently learned that the third grade team at Manhattan School for Children (Elizabeth Frankel-Rivera, Madelene Geswaldo, Alice Hsu and … More

# Closed to Open Array

After looking over beginning-of-the-year assessments, a new 4th grade teacher was concerned that half of her students were still unsure … More

# How to extend a string

We are often asked about how we can “stretch” strings beyond their place as a short mental math activity in … More