134 / 216
130
Copyright © 3P Learning – These resources have been created in partnership with Dr. Marian Small.
For more information visit
www.mathletics.comAdding with Blocks
Questions to facilitate the learning
•
What is the least possible number this could be?
•
Is there a greatest possible number?
•
Once you have one number, how can you use that to come up with another number?
•
Could your number have been represented by a different number of blocks? How many?
Scaffolding the learning
•
How could you show 100 with 10 blocks? Could you show it with a different number of blocks?
•
Do you have to use hundreds blocks for each number?
•
Do you have to use a thousands block as one of the blocks? If you do, how many other blocks do you
need to use to represent your number?
Extending the learning
Students might figure out how to subtract a 3-digit number represented with 15 blocks from a 4–digit
number represented with 20 blocks and end up with 23 blocks.
What’s the point of this task?
Aside from providing an opportunity for students to practice adding, this task requires lots of reasoning.
Many students will assume that if you add a 4-digit number using 20 blocks to a 3-digit number using
15 blocks, the total has 35 blocks; and, of course, it could. But the fact that it requires only 17 blocks
means that regrouping was used twice (e.g. 10 hundreds became 1 thousand, losing 9 blocks or 10
tens becomes 1 hundred, losing 9 blocks). The least possible answer is 1133 (which can be shown as 11
hundreds + 3 tens + 3 ones); the greatest has to be less than a 6-digit number since adding a 4-digit
number to a 3-digit number cannot yield more than a 5-digit number.
Number