Number Sense WipeOut
Calculator Game – WipeOut – a Place Value Game
What You Need:
– 1 calculator
– 2 players
How to Play:
- Enter any five or six-digit number into the calculator e.g. 23 458
- P1 asks P2 to subtracts a number on the calculator that will leave a zero in the Thousand’s column.
- P2 asks P1 to subtract a number that will leave a 1 in the Hundred’s column & then read that number aloud.
- P1 asks P2 to ‘wipe out’ the number in the Ten’s column to leave a zero & then read that number aloud.
- P2 asks P1 to ‘wipe out’ the number in the Unit’s column so that it is replaced by zero.
- P1 invites P2 to subtract a number that will leave only the number 100 visible on the calculator display.
How to Play:
– Take turns to subtract a number between 1 and 9 inclusive from the number displayed.
– The person who avoids making the calculator display zero is the winner.
For the Teacher:
– Play a game with the whole class discussing & demonstrating number strategies.
– Model a few games in front of the class with one calculator for you & one for each pair of students – computer calculator on IWB or data projector – draw the calculator display on the whiteboard.
– You are not to change the numbers in any other column. Only the column stated’.
– ‘Don’t forget to press the subtraction button on the calculator!!!’
– You must do the algorithm mentally and tell your partner the solution before you press the ‘equals’ button.
– press ‘equals’ to confirm – reflect on the strategy you used if you arrived at an incorrect answer.
– Discuss the developing stages of computations – use of fingers – use of strategies – automaticity – i.e. ‘See it, Say it’
– Fingers work for starters but are a slow inefficient strategy.
– Why might it be important to achieve ‘ automaticity’?
– Where are you at as a learner?
– I know that under stress I revert back to what I’m sure of. Discuss.
– Walk the room checking the tasks are being done – stand a short while behind the pair that you ‘suspect’ – you know the ones I mean 🙂
– Ask – ‘What numeral is in Tens of Thousands, Thousands, Hundreds, Tens, Units column?
– Ensure the students are verbalizing their thinking.
– Zero is a numeral – the letter O is a letter – insist students use mathematical vocabulary.
– What is the difference between a numeral and a number?
– Say ‘Gee Gee’ at the end of the game. It stands for ‘Good Game’.
Developing Number Strategies:
Play the game over a week with different skill/strategy focuses:
– only allowed to subtract 5
– only allowed to subtract 6 (-5 – 1 more)
– only allowed to subtract 7 (-5 – 2 more)
– only allowed to subtract 8 (-10 + 2 more)
– only allowed to subtract 9 (-10 + 1 more)
– Color in a hundreds grid to find the patterns.
– Discuss ‘Jumps to decades’.
– How can the ‘Facts to Ten’ help arrive at answers more quickly?
9+1, 8+2, 7+3, 6+4, 5=5, 4+6, 3+7, 2+8, 1+9
– What strategy works for you?
Something to reveal and explore after playing the game for a while 🙂
– Here is a sequence of numbers that will help you win the game every time if you start first.
– 91, 81, 71, 61, 51, 41, 31, 21, 11