Find the five distinct digits N, R, I, C and H in the following nomogram
115^2 = (110 x 120) + 25, that is 13225 895^2 = (890 x 900) + 25, that is 801025 Can you explain what is happening and generalise?
The sums of the squares of three related numbers is also a perfect square - can you explain why?
The squares of any 8 consecutive numbers can be arranged into two sets of four numbers with the same sum. True of false?
Find some triples of whole numbers a, b and c such that a^2 + b^2 + c^2 is a multiple of 4. Is it necessarily the case that a, b and c must all be even? If so, can you explain why?
Think of a number Multiply it by 3 Add 6 Take away your start number Divide by 2 Take away your number. (You have finished with 3!) HOW DOES THIS WORK?
Choose any four consecutive even numbers. Multiply the two middle numbers together. Multiply the first and last numbers. Now subtract your second answer from the first. Try it with your own. . . .
A job needs three men but in fact six people do it. When it is finished they are all paid the same. How much was paid in total, and much does each man get if the money is shared as Fred suggests?
Visitors to Earth from the distant planet of Zub-Zorna were amazed when they found out that when the digits in this multiplication were reversed, the answer was the same! Find a way to explain. . . .
If a two digit number has its digits reversed and the smaller of the two numbers is subtracted from the larger, prove the difference can never be prime.
We can show that (x + 1)² = x² + 2x + 1 by considering the area of an (x + 1) by (x + 1) square. Show in a similar way that (x + 2)² = x² + 4x + 4
Can you explain how this card trick works?
Think of a number and follow my instructions. Tell me your answer, and I'll tell you what you started with! Can you explain how I know?
Choose four consecutive whole numbers. Multiply the first and last numbers together. Multiply the middle pair together. What do you notice?
Think of a number and follow the machine's instructions... I know what your number is! Can you explain how I know?
Take any two numbers between 0 and 1. Prove that the sum of the numbers is always less than one plus their product?
Create some shapes by combining two or more rectangles. What can you say about the areas and perimeters of the shapes you can make?
If the sides of the triangle in the diagram are 3, 4 and 5, what is the area of the shaded square?
Find all the triples of numbers a, b, c such that each one of them plus the product of the other two is always 2.
Think of two whole numbers under 10, and follow the steps. I can work out both your numbers very quickly. How?
How many more miles must the car travel before the numbers on the milometer and the trip meter contain the same digits in the same order?
Pick a square within a multiplication square and add the numbers on each diagonal. What do you notice?
A 2-Digit number is squared. When this 2-digit number is reversed and squared, the difference between the squares is also a square. What is the 2-digit number?
Can you convince me of each of the following: If a square number is multiplied by a square number the product is ALWAYS a square number...
Find b where 3723(base 10) = 123(base b).
How good are you at finding the formula for a number pattern ?
I added together the first 'n' positive integers and found that my answer was a 3 digit number in which all the digits were the same...
A box has faces with areas 3, 12 and 25 square centimetres. What is the volume of the box?
The Number Jumbler can always work out your chosen symbol. Can you work out how?
Investigate how you can work out what day of the week your birthday will be on next year, and the year after...
Think of a two digit number, reverse the digits, and add the numbers together. Something special happens...
Sets of integers like 3, 4, 5 are called Pythagorean Triples, because they could be the lengths of the sides of a right-angled triangle. Can you find any more?
The well known Fibonacci sequence is 1 ,1, 2, 3, 5, 8, 13, 21.... How many Fibonacci sequences can you find containing the number 196 as one of the terms?
The diagram illustrates the formula: 1 + 3 + 5 + ... + (2n - 1) = n² Use the diagram to show that any odd number is the difference of two squares.
What are the possible dimensions of a rectangular hallway if the number of tiles around the perimeter is exactly half the total number of tiles?
Take any four digit number. Move the first digit to the end and move the rest along. Now add your two numbers. Did you get a multiple of 11?
Robert noticed some interesting patterns when he highlighted square numbers in a spreadsheet. Can you prove that the patterns will continue?
The number 27 is special because it is three times the sum of its digits 27 = 3 (2 + 7). Find some two digit numbers that are SEVEN times the sum of their digits (seven-up numbers)?
However did we manage before calculators? Is there an efficient way to do a square root if you have to do the work yourself?
32 x 38 = 30 x 40 + 2 x 8; 34 x 36 = 30 x 40 + 4 x 6; 56 x 54 = 50 x 60 + 6 x 4; 73 x 77 = 70 x 80 + 3 x 7 Verify and generalise if possible.
Crosses can be drawn on number grids of various sizes. What do you notice when you add opposite ends?
Given an equilateral triangle inside an isosceles triangle, can you find a relationship between the angles?
Use algebra to reason why 16 and 32 are impossible to create as the sum of consecutive numbers.
How many winning lines can you make in a three-dimensional version of noughts and crosses?
Attach weights of 1, 2, 4, and 8 units to the four attachment points on the bar. Move the bar from side to side until you find a balance point. Is it possible to predict that position?
Think of a number, add one, double it, take away 3, add the number you first thought of, add 7, divide by 3 and take away the number you first thought of. You should now be left with 2. How do I. . . .
Some students have been working out the number of strands needed for different sizes of cable. Can you make sense of their solutions?
How to build your own magic squares.
Can you use the diagram to prove the AM-GM inequality?
Pick the number of times a week that you eat chocolate. This number must be more than one but less than ten. Multiply this number by 2. Add 5 (for Sunday). Multiply by 50... Can you explain why it. . . .