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Calculating the difference: a discussion of the use of calculators in the English primary classroom
Clare Green looks at the role of the calculator in the teaching and learning of primary mathematics.
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Adding with the abacus
Nowadays the calculator is very familiar to many of us. What did
people do to save time working out more difficult problems before
the calculator existed?
problem
Mobile numbers
Age
5 to 11
Challenge level
In this investigation, you are challenged to make mobile phone
numbers which are easy to remember. What happens if you make a
sequence adding 2 each time?
problem
Secret number
Age
5 to 7
Challenge level
Annie and Ben are playing a game with a calculator. What was Annie's secret number?
problem
Clever keys
Age
7 to 11
Challenge level
On a calculator, make 15 by using only the 2 key and any of the
four operations keys. How many ways can you find to do it?
problem
A conversation piece
Age
7 to 11
Challenge level
Take the number 6 469 693 230 and divide it by the first ten prime
numbers and you'll find the most beautiful, most magic of all
numbers. What is it?
problem
Reverse trick
Age
7 to 11
Challenge level
Tell your friends that you have a strange calculator that turns
numbers backwards. What secret number do you have to enter to make
141 414 turn around?
game
Four go for two
Age
7 to 11
Challenge level
Four Go game for an adult and child. Will you be the first to have four numbers in a row on the number line?
problem
Exploring wild and wonderful number patterns
Age
7 to 11
Challenge level
EWWNP means Exploring Wild and Wonderful Number Patterns Created by Yourself! Investigate what happens if we create number patterns using some simple rules.
problem
It's all about 64
Age
7 to 11
Challenge level
Write the numbers up to 64 in an interesting way so that the shape they make at the end is interesting, different, more exciting ... than just a square.
problem
Book codes
Age
7 to 11
Challenge level
Look on the back of any modern book and you will find an ISBN code. Take this code and calculate this sum in the way shown. Can you see what the answers always have in common?
problem
Special 24
Age
7 to 11
Challenge level
Find another number that is one short of a square number and when
you double it and add 1, the result is also a square number.
problem
Forgot the numbers
Age
7 to 11
Challenge level
On my calculator I divided one whole number by another whole number and got the answer 3.125. If the numbers are both under 50, what are they?
problem
Number pattern explorations
Age
7 to 14
Challenge level
Investigate what happens if we create number patterns using some simple rules.
problem
One million to seven
Age
7 to 11
Challenge level
Start by putting one million (1 000 000) into the display of your
calculator. Can you reduce this to 7 using just the 7 key and add,
subtract, multiply, divide and equals as many times as you like?
problem
Largest product
Age
11 to 14
Challenge level
Which set of numbers that add to 100 have the largest product?
problem
Round and round and round
Age
11 to 14
Challenge level
Where will the point stop after it has turned through 30 000 degrees? I took out my calculator and typed 30 000 รท 360. How did this help?
problem
Adding all nine
Age
11 to 14
Challenge level
Make a set of numbers that use all the digits from 1 to 9, once and
once only. Add them up. The result is divisible by 9. Add each of
the digits in the new number. What is their sum? Now try some other
possibilities for yourself!
problem
Decimal time
Age
11 to 14
Challenge level
Use the clocks to investigate French decimal time in this problem.
Can you see how this time system worked?
problem
Triangle incircle iteration
Age
14 to 16
Challenge level
Keep constructing triangles in the incircle of the previous triangle. What happens?
problem
Dating made easier
Age
14 to 16
Challenge level
If a sum invested gains 10% each year how long before it has doubled its value?
problem
Climbing powers
Age
16 to 18
Challenge level
Does it make any difference how we write powers of powers?
problem
Rain or shine
Age
16 to 18
Challenge level
Predict future weather using the probability that tomorrow is wet given today is wet and the probability that tomorrow is wet given that today is dry.