**Question**: Can the *Investigations* units be taught in a different order than suggested?

**Answer**: The first edition of *Investigations* was written as a “replacement unit” model where individual units within a grade were somewhat less dependent on previous units, and schools and districts often chose their own sequence, or decided to teach only 3 or 4 units the first year of implementation. That was the 1990s! The units in the 2nd and 3rd editions were written as a complete, coherent, full-year curriculum and are intended to be taught in order. Whether it’s because people remember the first edition, or have specific reasons or issues, we often get asked about changing the sequence of units.

In the 3rd edition, the curriculum units at each grade level are intentionally and carefully sequenced. We strongly recommend that the units be taught in the intended order. All of the units in the number and operations strands (whole and rational numbers) absolutely need to be taught in order because concepts and skills are introduced and developed, and then built upon over the course of the year. We purposefully spaced out the number and operations units across the year. Students need time to sit with the ideas and use them in other contexts, before moving on to new ideas. The non-number units that are in between these units often utilize and reinforce previously taught number concepts and skills, particularly in the work that is the main focus of that unit (e.g. geometry or data) as well as in the ongoing review and practice features (i.e. Classroom Routines/Ten-Minute Math Activities and Daily Practice pages). Changing the sequence of units means these features may focus on content that isn’t appropriate or timely.

We do recognize that, in some districts, decisions may need to be made about the order of units in a specific grade for various reasons, the most common being the timing of the state assessment, or beliefs or preferences about what content they think should come first. (See Why Start with Multiplication and Division?, a Grade 3 Q&A.) We advise schools/districts to complete an entire year of instruction using the intended sequence before making any decision(s) to change the order. Then, the decision should be made collectively, rather than by an individual teacher. Such decisions should only be made after careful scrutiny of what was learned from teaching the units in order, the specific math content of a unit, and its position in the grade level sequence. (*Implementing *Investigations* at Grade X* is a useful resource in providing information that traces the development of content ideas within and across grade levels, as well as information about how the math in the Classroom Routines/Ten Minutes Math Activities develops over time.)

Have you thought about changing the order of the units? Tried it? We’d be interested in hearing about your experiences.

*We are excited to have a space that offers us the opportunity to answer common questions from the field. Have questions you’d like to see answered? Email us.*

- Reflections on NCSM/NCTM, Part 2 - April 29, 2019
- Reflections on NCSM/NCTM, Part 1 - April 22, 2019
- A Grade 2 Q&A: The Size of the Numbers - November 28, 2018

I am very curious about changing the order of the unit. My coworker would like to start with unit 3 because they think that the students need more practice in addition and subtraction before multiplication. But I feel that unit 1 is really addition but in another way. What is your recommendation?

Hi Jennifer, Thanks for your question. I’m actually going to point you to another Q&A blog post, about this very question! I hope it is helpful. https://investigations.terc.edu/grade-3-qa-start-multiplication-division/

Hello,

I am working with some teachers who are interested in changing the 4th grade unit sequence. Is there a resource that provides the thinking behind the unit order in that specific grade level? Thanks!

Hi Brian,

Much of what is in the blog above describes our rationale at all grade levels for the sequence of units—spacing out the number units so that have students have time “to sit with the ideas and use them in other contexts. . .”. This is certainly true for Grade 4. Here is a little more information specific to grade 4 that hopefully you’ll find useful.

In grade 4, the emphasis on work with the operations is on multiplication and division. There are three of these units, so it was important for us to spread those units throughout the year (Units 1, 3, and 7) with enough time between them for ideas to continue to grow and emerge. This growth (and time to sit with the ideas) occurs through the content of other units, as well as practice and review.

Some 4th grade teachers want to do Unit 5 (addition, subtraction, and the number system) first in the sequence because they see it as a “review” unit and starting with place value and addition/subtraction seems like a “good” start for Grade 4. This unit is not meant for review and practice–it’s a mathematical study of place value and the two operations. By waiting until mid-year or so to teach the unit, students have had many mathematical experiences that are an important aspect of getting the most out of the mathematics of this unit. (In the curriculum, students are expected to be fluent with addition and subtraction up to 1,000 by the end of grade 3.) Students are getting plenty of practice and review with addition and subtraction in the first 4 units, through the Ten-Minute Math activities and the homework and practice pages. They’re also working a lot with place value ideas, including things like what it means to multiply a number x 10.

There is some flexibility in the non-whole number units, although we’d still recommend that they be taught between the number units. Unit 6 (Fractions and Decimals) is strategically placed in the sequence after student have done three of the whole number units-concepts they learn in those units are important to understanding the concepts of fractions and decimals.

Feel free to let us know if you have other questions!