Number Strings

NUMBER STRINGS

CA/NY Mathematics Standard 2.NBT.5 - Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction. 

Mathematical Practice 1: Make sense of problems and persevere in solving them; 2: Reason abstractly and quantitatively; and 7: Look for and make use of structure.

I encountered number strings for the first time last week in Number Strings: Daily Computational Fluency and I wanted to play around with them and see what I could come up with. I put together the following general set of steps for developing a number string routine:

  1. Identify a strategy you want your students to practice (compensation, adding in chunks, etc.)

  2. Develop a sequence of math problems beginning with something the students can do and lead them toward a more difficult problem. The sequence should be designed to guide them toward using the target strategy, but they should not be discouraged from using other strategies.

  3. Gather students on the rug

  4. Write the first problem on the board, possibly lined up with a number line or another indicator of units.

  5. Allow students time to think.

  6. Ask them to share their thoughts with a partner.

  7. Ask for volunteers to share their strategies.

  8. Write “helper problems” on board and repeat the process, building on previous discussion.   

 

Designing these is much harder than I expected! But here are a couple of my first attempts.

I also found this great resource that provides examples of number strings for all of the mathematical operations: https://numberstrings.com/. It was created by Kara Imm and Rachel Lambert, two of the authors of the Number Strings article mentioned above.

Example 1: Decomposition

Problem set:

 

Connecting background knowledge & practicing the strategy:

Asking students to transfer their knowledge to a new problem:

Example 2: Compensation or Making Tens

Problem set:


Connecting background knowledge & practicing the strategy:


Practicing the strategy (continued) & asking students to transfer their knowledge to a new problem:


Comments

Post a Comment

Popular posts from this blog

Teaching students how to solve (+/-) word problems

I want to learn how to teach 2nd grade students how to select the appropriate operation (addition or subtraction) to solve word problems.  NY-2.OA.1a Practices 1&2 When my daughter was in 2nd grade she knew what to do when she was presented with 8+3=__ or 10-4=__ but if she was given a word problem that didn’t explicitly say “add” or “subtract” she would often just guess which operation was appropriate. Her teacher sent home a study guide titled “How do we know if we add or subtract in word problems?” Under the heading “Key Words for Addition” it said Sum, Total, Altogether, Plus, and In all. Under the heading “Key Words for Subtraction” it said Remainder, Difference, Less than, Fewer, How many more?, Minus, and How Many Left? This guide was helpful to an extent but my daughter didn’t always remember to look at it and sometimes couldn’t find it at home (and I had no idea if she had it available for use at school). As her parent, I tried to talk her through the word problems, sh...
Read more

Central Tendency: Mean, Median, and Mode

Central Tendency: Mean, Median, and Mode  Content Standards: CA/NY.6.SP.5.A,B,C&D This week I wanted to refresh my memory about central tendency in data sets. Central tendency is a way of describing a ‘typical’ member of a set of results based on the characteristics of that member. The most common ways of describing central tendency are mean, median, and mode. Khan Academy has a great set of videos that explain these in detail, beginning with this one: Statistics intro: Mean, median, & mode (video) .  Once I was reminded of what they all mean, I wanted to develop “real life” scenarios that would get my students to explore mean, median, and mode. I found this video that gave some example problems and does a good job of explaining why you might use mean or median or mode in a given situation: (Video) Word Problems: When to Use Mean, Median, and Mode   I also wanted to find a way to get students to explore these concepts without simply giving them word problems, but ...
Read more

Dividing Fractions

The reading this week, "Two Ways of Thinking about Division," helped me to understand something I had really been struggling with:  I couldn't imagine how to represent dividing fractions visually. Until I read that article, I would have only been able to describe the procedure for dividing fractions, not demonstrate where the answer came from. Even so, the description of the area model was difficult to digest. I looked at the  links that were provided at the bottom of the "Two Ways" article and  I found this method a little easier to wrap my head around:  Divide Fractions with Circle Models (visualfractions.com) .  These videos from Khan Academy were also helpful: https://www.khanacademy.org/math/cc-sixth-grade-math/cc-6th-arithmetic-operations/cc-6th-dividing-fractions/v/visually-dividing-a-fraction-by-a-whole-number    https://www.khanacademy.org/math/cc-fifth-grade-math/divide-fractions/imp-dividing-unit-fractions-by-whole-numbers/v/visually-dividin...
Read more