Activities to use with the 100s Board

Number Sense Children with well-developed number sense use numbers to solve problems. They make sense of numerical situations, and use what they know to figure out what they don’t know. To have good number sense, children must understand the following basic concepts: counting, number relationships, decomposing and composing numbers, and landmark numbers.

Observations About the 100’s Board  What do you notice about the numbers in the last column?  Where are all the numbers with a 3 in the one’s place?  Where are all the numbers with zeros in them?

Compare to the 0-99 Board  Decade numbers are on the left. Some teachers prefer this to the 100’s chart because each horizontal row has the same number of 10’s. For instance, the second row of the hundred’s chart ends in 20, whereas the entire 3 rd row of the 0-99 chart begins with 2 tens, or 20.

Exploring the Hundreds Chart  Count by 5’s. Shade those numbers with lavender. Count by 3’s. ‘X’ those numbers in red.  Count by 2’s. Shade those numbers yellow. Count by 4’s. ‘X’ those numbers purple.  Count by 9’s and shade those numbers one color. Count by 11’s and shade those numbers another color.  What patterns do you see?

Hundreds Board Cover-Ups  Place cut out puzzle pieces on the overhead 100’s board. Students should tell which numbers have been covered and how they knew. Is there another way to determine the missing numbers?  Introduce concepts such as 10 more, 10 fewer, 1 more, 1 fewer. (Process Standards: Reasoning and Proof; Communications, Representations)

Clear Pieces With 1 Number Given  Ask students to determine the surrounding numbers.  How were they determined?  If I ask you to close your eyes and to picture where you though 65 would be, could you describe for us what you see?  Where would it be? How do you know?  That’s Number Sense

How Many Questions?  Play one or two rounds of “How Many Questions?” You think of a number and students need to guess your number by asking questions that can be answered Yes or No.  Based on the answer to the question the students will describe to you which numbers should be crossed off the Hundreds Board to indicate that they have been eliminated.  The goal is to determine the number with the fewest number of questions.

How Many Questions Cont.  Ideally the students will quickly discover that questions such as: “Is the number even (odd)?” and “Is the number greater than (less than) 50?” are good questions to begin with because half of the numbers can be eliminated.  Questions such as “Is the number 74?” are better left until the end when there are only a few numbers remaining.  Keep a tally to show how many questions are asked. See if the group can ask fewer questions the next time they play.

What’s My Rule?  Create transparencies that illustrate the rules listed below. Display the transparencies one at a time and have students identify the rule that describes the numbers that are shaded. Even Numbers Numbers that have 4 as one of the digits Multiples of 11 (or double digit numbers) Multiples of 4 Numbers whose digits sum to 8

What’s My Rule? Cont. Numbers whose digits differ by one Numbers whose digits in the tens place is less than the digit in the ones place Multiples of 9 (if 99 is NOT shaded it could also be Numbers whose digits sum to 9)  Once students are comfortable with identifying the rules they can create puzzles of their own (This can be very difficult. Students often create puzzles that “sort-of” follow their rule but are not entirely accurate)

Story Problems  Luke played ball for 29 minutes. Then he rode his bike for 34 minutes. How many minutes did Luke spend doing these two things?  Papi had 82 slices of pizza in his shop. He sold 56 slices to his customers. How many slices does Papi have left?  Marissa has 26 stickers. Her sticker album will hold 72 stickers. How many stickers does she need to fill her album?

Story Problems Cont.  There are 3 tennis balls in each can, how many tennis balls are in 4 cans?  A spider has 8 legs. How many legs do 3 spiders have?  We made 20 muffins for the bake sale. We put muffins in bags to sell. We put 4 muffins in each bag. How many bags of muffins did we have to sell?

Multiples  Demonstrate how the Hundred Boards can be used to illustrate multiples. Share student transparency that shows multiples of 3. Describe the pattern.  Using crayons, have students shade multiples of their choosing and describe the pattern that is visible

Arrow Math  Use the arrow math transparency to explain how Arrow Math works. Challenge students to find the solutions to the problems below using their Hundred Boards or mental math. 45 → → ↑ 53 ↓ ← ↓ → → 17 ↓ ← 75 ↑ ← → ↓ ↓

What Number am I?  I am between 1 and 20. I am less than 10. I am odd. I am prime. I am a factor of 20. What number am I?  I am less than 40. My digits are both multiples of 3. I am 1 less than a multiple of 5. What number am I?  I am a square number. I am a multiple of 2. I am less than 100. My digits add to less than 9. What number am I?

Get It Together Math Problems for Groups Equals Lawrence Hall of Science © 1989 by the Regents of the University of California