Counting

Students practice counting and writing numbers from 1 to 25. Download printable puzzle-sheets here. Some are purposefully impossible.

Make your math class active by teaching real skipping. In this video we go forward, backward and stand still on the number line.

Give your students practice in skip counting. Download the puzzle-sheets here.

Give your students practice skip counting through a magic trick.

For one class teachers should just count and count and count. There is no better way to show the relative size of numbers. Cheating after 200 is allowed 😉

Stack 10 blocks to make any number of towers… the heights of the towers must be different. The king wants to see ALL the solutions!

Snap shut on your opponent’s caterpillar before they can snap shut on yours.

This is a game of deduction and decimals.

Each team is dealt seven secret cards with numbers chosen from: 3.81, 3.82, 3.83 … 4 … 4.19, 4.2, 4.21, 4.22.

(Notice that we use 4 and 4.2 instead of 4.00 and 4.20. This is on purpose so that students get experience ordering numbers with a different number of digits after the decimal point.)

Each team takes time to organize their seven cards to form a caterpillar from smallest (on the left) to largest (on the right). The numbers are kept hidden from the opponents. Our caterpillar is on the bottom starting with 3.85.

Your opponent’s caterpillar is unknown at the top.

Each team gets 5 secret cards in their hand. Ours are shown in the middle of the slide. We can’t see the opponent’s hand.

On your turn:

1) Give one of the cards in your hand to your opponent. They must place it in the correct place in their caterpillar.

We know all the numbers to the left of 3.95 are smaller than it, and all the numbers to the right are bigger.

On your turn:

2) Guess a number that you think is part of the opponent’s caterpillar. If you are right, they must flip it over and you get to guess again until you’re wrong. Our first guess (4) was right, but our second guess (4.05) was wrong.

On your turn:

3) Draw a card if there are any left in the deck.

Now it is your opponent’s turn, but let’s jump forward in the game…

Remember that the cards go from 3.81 to 4.22. Take a moment and try to figure out something about your opponent’s caterpillar.

Hint: The two rightmost cards are more than 4.18.

Answer: The two cards on the right must be 4.19 and 4.21 because we can see the other two cards that are more than 4.18.

Okay – it is our turn. Let’s give our opponent 3.88 from our hand to place in the correct spot along their caterpillar.

Our opponent places it at the right spot.

Next we will guess a number. Here is where the game gets interesting. We know that the right two numbers are 4.19 and 4.21, but if we guess them now it will give our opponent information about our own card 4.2, so let’s wait and guess something we are less sure about… 3.84

We’ve been lucky. We get to guess again. Let’s choose 4.13. Now we know that our opponent will answer no, because it is part of our caterpillar, but this little bit of deception might confuse our opponent.

Lastly we draw a new card.

We win the game if we expose all of our opponent’s caterpillar.

Some number systems use place value – others do not. This video takes you on a tour of number systems including Egyptian, Arabic, Babylonian, Montessori and Scientific Notation.