What's happening in Math class this week
We started a multi-day investigation of packages and parcels. Each present in the story
problems is represented by a square, and each box of 10 presents is represented by a larger
rectangle. We practiced identifying the value from drawings, and
making our own drawings to represent numbers. We then moved on
to using these drawings in addition story problems. This work is
aimed at continuing to construct unitizing of tens, develop place value
concepts, and develop strategies based on using friendly numbers
(multiples of ten).
We also played a Three Digit Numbers game. It came home, tucked
into the homework book. Please play it this week and follow the
example of representing the values with drawings and expanded form.
This was another week spent constructing the two meanings of division. Depending on the
scenario, we divide to find either the number of groups or the number of items in the groups.
We assessed lots of division story problems to see kind of division there were.
The kids made posters of their work solving story problems and we held a math conference.
The kids did a great job of listening to each other, trying to make sense of others’ work, and
asking questions. They identified the strategies used and the pros and cons of each strategy.
The strategies we looked at are:
• Dealing out by ones
• Skip counting
• Using related multiplication facts
• Using ratio tables
Depending on the numerical relationships you have developed, you can access the more
sophisticated strategies. Our goal is not to leave kids in the least sophisticated strategies of
dealing out and skip counting, but to use related multiplication facts and known facts on a
ratio table. So, our work here is not finished yet.
We did more adding of decimals with the give-and-take
strategy. After doing the workout activity about this, the kids
had a much better sense of how to use this strategy. We could
then compare the chunks used for give-and-take to determine
which moves were more efficient.
They did great work this week dividing by two-digit numbers
using the array model. For example, we divided 276 by 23.
We used the base ten pieces to build the 276 into a rectangle
with a side of 23. The challenge is to find the other
dimension of the rectangle. Kids do this first with physical
objects (the base ten pieces), then with drawings of open
arrays to show the division.
We finished the Building Formulas unit with
investigations on maximum and target heart rates,
temperature effecting cricket chirp rates, and
proportions in Egyptian drawings. We did a lot of
arrow strings and reverse arrow strings (a conceptual
model for order of operations). We made graphs
from data and explored how scaling the axes
differently effected the graph. This is a picture of
them all quietly working— the quiet part made it a rare occurrence.