Math Update

We have been studying larger 2-digit numbers.  We noticed that every 2-digit number has a place to show the tens hiding inside, along with a place to show the extra ones.  We also represented these numbers using ten sticks and circles, and wrote an equation to match our work.

Then we worked on adding two 2-digit numbers together and solved it the same way: by drawing ten sticks and circles.

As first graders, we have become experts at using these symbols to support our thinking.  In order to be accurate, we know that our tens and circles have to match our numbers and they must be lined up neatly, with five groups clearly showing, so it’s easy for us to ring a 10.

We have also tried the one ten below strategy:

We even learned the show-all strategy:

Whatever strategy your first grader feels the most comfortable with he or she is welcome to use.  Our goal is to be accurate and to understand that sometimes when we add two two-digit numbers together – we make a new ten!!!

Math Update

This past week our mathematicians studied measurement.  We discussed how in the old days before rulers were invented, people used to use their body parts to measure objects.  This kids couldn’t believe this was true and brought up a very big problem… our feet and fingers are different sizes!  We realized that when we use a common unit – like a paperclip – we all get the same results.  To test this theory, we used paperclips to measure various things in our math book and around the room.

We also introduced the word “length” and talked about how to line up measurement tools properly to get the most accurate measurement.  We compared lengths of objects from shortest to longest and longest to shortest (1, 2, 3)

At the end of the week we took our Unit 7 assessment – our first graders did great!!!  Next week, we will start our last math unit on 2-digit addition!!

Math Update

During our math time this week we studied some familiar shapes: rectangles, squares, triangles and circles.  We learned that every shape has special attributes that are always true!!
We also learned that shapes can be divided into equal parts.  When a shape is broken into two equal parts we call these halves.  When a shape is broken into four equal parts we call these fourths.  It’s important to understand halves and fourths especially when we are trying to share something (like a pizza, cookie or granola bar) equally.

We continued to study shapes during our math time this week.  We started the week combining triangles, rectangles and squares to form new shapes.  We learned about: rhombuses, trapezoids, parallelograms, and hexagons.  We also found that we could combine and transpose our shapes to create patterns.

Later in the week we began exploring with 3-dimensional shapes! We touched on the following shapes…

We learned about the attributes of each of these shapes.  We also briefly discussed how these 3-D shapes compare to the 2-D shapes. For example: the 3-D sphere is just like a 2-D circle and the 3-D rectangular prism is just like a 2-D rectangle.  We combined different shapes together to create new shapes and also tried to break large shapes apart into smaller ones.

Math Update

This week, our mathematicians learned how to tell time to the hour and half hour!! They learned that the two different kinds of clocks that we use in everyday life are called an “analog” clock or a “digital” clock. We discussed that the shorter hand always points to the hours and the longer hand always points the minutes.

We spent lots of time reviewing and practicing drawing the time on an analog clock and on a digital clock!  The hardest part for the kids is to remember that when it is a half hour, the hour hand is half way past that hour (they often read it as the next hour ahead instead of the hour it is half past).

Math Update

For the last few weeks, we have created graphs and made comparisons during our math switch time.  As our expertise grew, so did our graphs! Instead of comparing just two groups of objects, most of our graphs now compare three categories of data, like the graph below:

We are always trying to make comparisons between the data in each category (group) by finding the MAGIC NUMBER. With three groups it’s a little harder to find the difference especially when comparing the top category of data with the bottom category of data. If we use a pencil to cover up the extra information, finding the MAGIC NUMBER is a breeze.

The rest of our time during math switch has been spent solving comparison stories. Our first graders learned a new strategy called: COMPARISON BARS. Comparison bars are a visual tool for solving stories in which two amounts are compared and the difference (magic number) is either known or unknown. Check out the examples below:

Thank you for helping your child use comparison bars on his or her homework pages this week. Be sure to check their work. This new strategy is tricky and sometimes our first graders are unsure about where the known information should go. (If the magic number or the difference is known, this information always goes inside the circle.) We will review more comparison stories next week and then we will wrap up Unit 6 with an assessment.

Math Update

We began our Unit 6 in math this past week.  Our first grade mathematicians our now sorting, organizing, and comparing data.  What a blast!!

To start things off, we learned how to take random data and record it on a chart or graph.  Crossing out each object as we add it to our graph helps us to be accurate in our representation.

After graphing the information, we were able to notice many things about the data we were studying.  Which group had the most?  Which group had the fewest?  How many in all?  And, we were also able to make comparisons – how many more or how many fewer.  To compare our data, we drew matching pairs and then circled the magic number.

The magic number represents the difference between the two groups being compared.  No matter if we are comparing how many more or how many fewer – the number is always the same (that’s why it’s magic!).

When you are looking over your first grader’s homework be sure to check if he or she is circling the word that correctly matches the data.  Understanding when to circle more or fewer can be a little tricky especially if your first grader is reading the homework page on their own.  We always underline the group that is listed first, so we know which part of our graph to go back and study.

Math Update

During our math time this past week, we spent time studying our 120 number grid.  We noticed patterns in the ones place and tens place going across the grid and down the grid.  We also used our number grid to find 10 more and 10 less than a number.

While our number grid can be very helpful, it’s not our only tool for adding ten more and ten less.  We can also use our ten sticks find the answer when adding and subtracting tens.

Check in with your child at home to see if he or she can count up to 120!!

Math Update

During our math time this week, we continued to solve missing partner and missing total stories.  We also revisited a concept that was first introduced back in October.  We used our understanding of the partners in an addition equation to help us find the missing partner in a subtraction equation, but this time we were working with teen totals.

Next week, we will be working on counting and writing numbers up to 120. To help your first grader practice this skill, have him/her start at any 2 digit number and then count out loud to 120. This could be a great activity to do together in the car. As an extra challenge, you can even have your child write the numerals up to 120!

Math Update

During our math time this week we continued to break apart larger numbers into smaller partners. We used whiteboards and markers, counters, stair steppers, and activities from our math workbook to visualize the partners, switch partners, and doubles partners for the numbers 8, 9, and 10. Challenging your first grader to write and show each set of partners in a variety of ways has helped to increase number sense and flexibility with these numbers.

We also continued to use our knowledge of partners and patterns to practice addition (+0, +1, +2) and subtraction (-0, -1, -2) facts. This week in particular, we practiced adding and subtracting doubles partners (1+1, 2-1, 2+2, 4-2, 3+3, 6-3, etc.), and discovered that a number minus itself equals 0 (8-8 = 0). Next week, we will take our Unit 1 math assessment and also pretest for Unit 2.