The Best Place Value Experience for 2nd Graders!

2nd graders need lots of experience decomposing numbers as they work with place value concepts. I often see these guys carefully pulling numbers apart: "167 is one hundred, 6 tens, and 7 ones". They are correct, but are they truly understanding place value with this exercise or just memorizing hundreds, tens and ones?

To check whether students are really thinking things through, I introduce an activity with brown paper bags. Inside the bag are flats (100s), rods (10s) and cubes (1s)

I label the bag with a number and fill the bag with a different combination of base ten blocks. Students are not allowed to open the bag!

They can pick it up to feel the weight, they can shake it up a bit, but they can't look inside. They need to make an educated guess about what combination of blocks are inside the bag. 


The bag labeled 147 can be composed of different combinations:
147 cubes
1 flat, 4 rods and 7 cubes
1 flat, 3 rods and 17 cubes
1 flat, 2 rods and 27 cubes
1 flat, 1 rod and 37 cubes
1 flat, and 47 cubes
14 rods and 7 cubes
and so on...........

It is a lot of fun for students, and as they record their guesses, they begin to really delve deeply into the concept of place value. 

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