Estimating Length and Selecting Tools Unit of Study: Length in Customary Units Global Concept Guide: 2 of 3

Content Development  Estimation provides intrinsic motivation to measurement activities. It is fun to see how close you can come in your estimate or if your team can make a better estimate than the other teams in the room. (Van de Walle, 2006)  Estimation helps develop familiarity with the unit. If students estimate the height of the door in feet before measuring, they need to devise some way to think abou the size of a foot. (Van de Walle, 2006)

Day 1  The goal of this day is for students to estimate length in inches and feet.  Isolating inches and feet when estimating keeps students from making connections between the units and determining which would be more appropriate. Therefore, teachers using Go Math lessons 8.3 and 8.7 will want to blend the lesson essentials.  See GCG Lesson Ideas “Inching Along”. This link is a worksheet; however, it is better utilized as a classroom activity for estimation.

Day 2  Students need to learn, through hands-on experiences, that an inch ruler is a more appropriate tool to use to measure small objects while yardsticks and measuring tapes are more appropriate for larger objects. Additionally, students build understanding that a measuring tape is more appropriate to measure a curved surface.  See “Estimation Games” link in GCG for interactive estimation activities. Teachers will want to include using a measuring tape in this activity.

Day 3  Students need to make connections between estimation and measuring tools. E.g. If a student estimates that their math book is less than a foot, they will select an inch ruler to measure the book. Students might estimate the classroom to be 20 feet wide. Engage the students to discuss which tool would be most appropriate and why.  See “Kangaroo Jumps” Link in GCG Lesson ideas. This is a two day lesson addressing measurement. Teachers will want to focus on the activity where students become kangaroos. Students estimate, select a tool and measure.

Enrich/Reteach/Intervention  Enrich  Enrich TE pg. 417B – students select objects around the school, select a tool and record measurement  Go Deeper TE pg. 419 – students measure the same object with three different tools and determine which is most effective  Enrich E79  Reteach  RtI Tier 2 TE pg. 13B - estimation  Reteach 8.8 Student Page R84 –choosing a tool

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