# Clip 21/29: Day 2 Lesson Part F

## Overview

As her 5th-grade students finish their card sorts and defend their thinking, Erika Isomura increases the rigor, inviting pairs to go beyond just solving the problem: “Make something challenging, make something that the other kids are going to be like ... then after they think about it like ‘oh yes, I got it.’ Give them a little bit of a push, okay?” She connects their thinking back to the [previous lesson with fractional lengths of strings](http://www.insidemathematics.org/classroom-videos/public-lessons/5th-gr…).