# What's happening in Math class this week

Oak Class

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.

Elm Class

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.

Sequoia Class

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.

Redwood Class

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.