The Hundred Square

"Let's use this handy map to help us go exploring!"

"Huh, what's that on the back of the map?" "What are all of these numbers for, and why are some of them missing?" "Treasure!" "Treeeaaaaaasure!"

Skylar and Henry want to find some treasure, but first, they need to learn more about the hundred square. What is a hundred square? A hundred square is a tool we can use to count, see patterns and even add or subtract. It has the numbers one to one hundred organised into columns and rows.

Looking at the squares, you can see they count forwards by one each time in rows of ten. You might be able to see a pattern in the ones place of each number. For example, let’s look at the column that has the number two at the top. If you look at the ones place in every number of this column, what do you see? Every square vertically has the number two in its ones place. You might notice other patterns as well, like here, where the squares horizontally have the number one in the tens place until we reach twenty. When we read a hundred square, we read it the same way that we read a book, from left to right. Like reading, when we get to the last number on the right we go down to the next row and start from the left again. It looks like Henry and Skylar found something! "Henry, look, a box!" "Is it a clue? I think that's what's missing!" Let's help Henry and Skylar work out where this number goes on the hundred square so they can get closer to the treasure! When there is a missing number on a hundred square, you can use counting and patterns to help work out which number it is. Henry and Skylar's number is sixteen. Where should sixteen go on the hundred square? Sixteen has a one in the tens place so it will go with the other teen numbers that follow this pattern. Let's count the teen numbers to find out where it goes! Eleven, twelve, thirteen, fourteen, fifteen, sixteen. We found it! Sixteen goes after fifteen. "A spanner! We can use that to tighten the wheels and get to the treasure!" While Henry was tightening the wheels, Skylar noticed another number box!

Let's use what we know about the hundred square to help them work out where this number goes. Their next number is forty-four. Since forty-four begins with four, we can start with this row, and count up until we find its place. Count with me! Forty, forty-one, forty-two, forty-three, forty-four! So, forty-four goes after forty-three! "We got oil! Maybe if we put this on the wheels it will make the train faster and get to the treasure." Before we see what the treasure is, let's review. Today we learnt about the hundred square. It's a tool with numbers to help count, see patterns, and even add or subtract. We saw how it is organised with columns and rows and explored how to find missing numbers. Now, let's go and see that treasure! "I wonder what the treasure will be!" "We're here, we're here! We made it to the treasure!" "Look Skylar, a house! Our treasure is a house!" "Wait a second Henry, that's OUR house."