What number is hiding under the pig?
How do you know?
Imagine asking a class of 5th graders to determine what numbers are hidden behind each animal character on the number line shown above – a rich mathematical discussion is sure to follow as students begin discussing the values and HOW they knew and then going on to explain their mathematical approach to discovering the value of the hidden number. You may be surprised at just how many ways this simple question can be tackled.
What were the thinking steps you used to come to the specific number you believe is hiding?
- Did you begin with the zero and use a trial and error method?
- Perhaps you started with the 0.9 and worked backward toward the zero to determine the intervals?
- Perhaps you needed a subtraction equation to calculate the difference between known values?
- Or maybe it was a division problem that moved you toward the solution?
- Some may have noticed that the pig was exactly in the middle of 0.9 and 2.1, so considering the interval difference and dividing by two became central to determining the midpoint's value?
- Can you see how compensation might help to efficiently and easily find the value hiding under the pig? (adjust by 0.1 and think of 0.9 as 1 and 2.1 and 2)
The HIDDEN NUMBERS activity is interactive only when downloaded. Download it as either a Smart Notebook activity to use with interactive Smart whiteboards OR download the Powerpoint version that can be used on any device.
Download OPTION 1:
Notebook version for the SmartBoard - CLICK HERE – This version is available only to CCPS employees and requires log in to your Office 365 account. Download OPTION 2: Hidden Numbers - Universal download in Powerpoint format - CLICK HERE - this link makes the activity available to anyone |
When you download the Smart Notebook file, the slides are designed with animated features so that when you click on each character, the hidden numbers appear. The file contains 22 interactive lessons for grades PreK through Grade 5, including the activities shown below!
Recommended for PreK and up
Recommended for Grade 2 and up
Recommended for Grade 2 and up
Recommended for Grade 3 and up
Recommended for Grade 5 and up
Want even more reasoning activities?
Check out two of my favorite classroom-ready websites that help to develop mathematical reasoning and number sense:
The object of the Which One Doesn't Belong? activity is to find ways that 3 of the numbers are mathematically alike and to eliminate one of the numbers because it does not fit the mathematical rule of the other 3 numbers. Students try to eliminate EACH of the four numbers in as many ways as they can. Notice how much math talk happens as we take a look at some possible responses for the middle set of numbers above:
NUMBERS:
- The 9 does not belong because its digits do not have a sum of 7 (1+6=7 4+3=7 2+5=7)
- The 16 does not belong because it is not an odd number
- The 43 does not belong because it is not a perfect square (9=3x3 16=4x4 25=5x5)
- The 25 does not belong because it is the only one that is equivalent to one of our US coin values
- What other reasons can you find to eliminate one of the numbers?
I love these SPLAT! games created by Steve Wyborney. If you go to the website link above, you can get the first 20 game boards emailed to you by clinking the link in the lower right on the web page. All of Steve's game boards are free and he has a large series of game boards that has a wide range of levels that get progressively more rigorous. The one above would be great for our primary students. The 7 tells how many dots there are in total. By looking at the picture, can you tell that there must be 4 dots hiding under the Splat!? Intermediate grades, be sure to check out the Fraction Splat! game boards, too!
