Posts by: toni
Take a sheet of paper 20 cm by 20 cm and make a box without a lid by cutting out a square at each corner and folding up the flaps. What is the volume of your box?
Make boxes with different volumes by varying the sizes of the squares that you cut […]
1. Find the area of the quadrilateral.
2. The rectangle is cut into two pieces along the dotted line and rearranged to make a triangle. Find the perimeter of the triangle.
The diagram shows a septagon ABCDEFG in which the lengths GA, AB, BC, CD, DE, EF are all equal and FG = 6 units. The area of the square BDFG is half the area of the septagon. Find the perimeter of the septagon.
If three of the four expressions: 2x – 3 and x + 8 and 2x + 3 and 30 – x are equal, find their value and which expression is the odd one out.
Copy and label the diagram and explain the connection between the diagram and the first part of the […]
Add up these 3 equations. What do you notice?
Find the values of x, y and z.
Now add up all 5 equations given below. What do you notice?
b + c + d + e = 4
a + c + d + e = 5
a + […]
Here is an alternative version of the “Think of a Number” trick.
Think of two whole numbers under 10.
Take one of them and add 1.
Multiply by 5.
Add 1 again.
Double your answer.
Subtract 1.
Add your second number.
Add 2.
Double […]
Is it always possible, from any set of five positive whole numbers, to choose three numbers that add up to a multiple of 3?
For example, if you start with 4, 7, 11, 12 and 18, you can choose 4, 11 and 12 which add up to 27 (a multiple of 3).
[…]
Each shape has a different value. The totals for the rows and columns are given. Can you find the values and the total of the first column?
Click here for the Notes for Teachers.
This problem is adapted from the NRICH task What’s it worth? with permission of the University […]
In some countries temperature is measured in degrees Celsius (originally called degrees Centigrade) and in other countries it is measured in degrees Fahrenheit.
The freezing point of water is 0 degrees Celsius and 32 degrees Fahrenheit.
The boiling point of water is 100 degrees Celsius and 212 degrees Fahrenheit.
Draw a graph […]
Explain how the diagrams show how to work out 13 times 13 and (x+1) times (x+1).
Draw similar diagrams for 15 times 15 and (x+2) times (x+2).
Draw your own diagrams and use the same method to find the algebraic expressions for and and work out the expansion […]
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