Showing posts with label subtraction. Show all posts
Showing posts with label subtraction. Show all posts

Friday, August 29, 2014

Day 3

Day 3.

Also known as the day I pissed off most of my students, on purpose.

I didn't plan to irritate them.

We did our number talk and it involved a subtraction problem with lots of regrouping.  After walking around and seeing my students' answers, I noticed about half of them got the answer right. Others were having calculation issues or subtracting from left to right and getting all confused.

So I started the problem and asked what my next step was (it was regrouping).  The answer I got was to add a "1" to the one's place.  I asked if I was adding one or ten. I was told one.  I asked where this one came from. No one could tell me.

Face palm.  This does not bode well for math this year.

So we stopped solving the problem.

I gave them a two digit subtraction problem instead: 51-37.  Almost all of them got it right with the algorithm.  I saw one student try with a number line (yay!).   Then I modeled the problem with manipulatives (rods and cubes).



I explained that when we are regrouping, I'm not adding numbers out of no where.  I'm taking a set of ten from the next place value and redistributing them.  I wish I had these to use to show them actually breaking apart a set of ten:



But alas, I don't.

I gave them another problem to solve, both numerically and with a picture.  Most of them got it right using both ways.

Next week we'll go back to larger place values.  We'll also use manipulatives because they don't have enough hands on experience with making groups.  I've got some large gaps to fill!

After math, I asked them how they felt using this system:



Most of what I got in response was this:



They aren't there yet.  They told me they need more practice.  I told them good.  

I got a lot of confused faces.

I told them that in math, they aren't going get the concept on the first day. I told them I'm going to require multiple ways of thinking about the problem.  I told them they're going to have to prove they understand what is happening with the math, not just show me the right answer.

Many of my higher students are not happy with this challenge.  

To them, I say good. They'll be better off in the long run.  I had some grumpy math faces today!

Friday, February 21, 2014

Building Number Sense

I stumbled upon this idea online:



I love it! It's easily recreatable and truly lets students see the value of numbers.  What a great, easy way to build number sense...especially in the primary grades!  This could easily be used to compare two numbers and to build on addition and subtraction concepts.  Families could easily work on math sense at home with these cards as well.

Saturday, November 16, 2013

RACE strategy

During our intervention part of the day, I've been working with students on subtracting decimals to the thousandths, figurative language, theme and poetry.

We moved into working with constructed responses and one of my favorite strategies is RACE:



RACE stands for:

Restate the question.  Students use words from the question to formulate their opening or topic sentence.  This helps them to focus their answer.

Answer the question(s) that are asked.  For our district, constructed responses tend to have several parts and it's important for students to answer all portions.

C: Complete sentences.  Students need to remember the rules of grammar, spelling, etc when writing their responses.  We went over that one sentence does not suffice.

E: Evidence your answer, twice.  This helps them with main idea and key supporting details, as well as quoting accurately or inferring details from the passage.