Other tags that relate to Starfish Spotting
Factors and multiples. Games. Generalising. Describing patterns and sequences. Investigations. Addition & subtraction. Multiplication & division. Trial and improvement. Combinations. Working systematically.There are 218 results
Broad Topics > Calculations and Numerical Methods > Addition & subtraction
Starfish Spotting
Age 5 to 7
Challenge Level
How many starfish could there be on the beach, and how many children, if I can see 28 arms?
Exploring Wild & 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.
A-magical Number Maze
Age 7 to 11
Challenge Level
This magic square has operations written in it, to make it into a maze. Start wherever you like, go through every cell and go out a total of 15!
Month Mania
Age 5 to 11
Challenge Level
Can you design a new shape for the twenty-eight squares and arrange the numbers in a logical way? What patterns do you notice?
Arranging the Tables
Age 7 to 11
Challenge Level
There are 44 people coming to a dinner party. There are 15 square tables that seat 4 people. Find a way to seat the 44 people using all 15 tables, with no empty places.
What's in a Name?
Age 5 to 7
Challenge Level
What do you notice about these squares of numbers? What is the same? What is different?
Abundant Numbers
Age 7 to 11
Challenge Level
48 is called an abundant number because it is less than the sum of its factors (without itself). Can you find some more abundant numbers?
Calendar Calculations
Age 7 to 11
Challenge Level
Try adding together the dates of all the days in one week. Now multiply the first date by 7 and add 21. Can you explain what happens?
Caterpillars
Age 5 to 7
Challenge Level
These caterpillars have 16 parts. What different shapes do they make if each part lies in the small squares of a 4 by 4 square?
Rabbits in the Pen
Age 7 to 11
Challenge Level
Using the statements, can you work out how many of each type of rabbit there are in these pens?
The Deca Tree
Age 7 to 11
Challenge Level
Find out what a Deca Tree is and then work out how many leaves there will be after the woodcutter has cut off a trunk, a branch, a twig and a leaf.
The Add and Take-away Path
Age 5 to 7
Challenge Level
Two children made up a game as they walked along the garden paths. Can you find out their scores? Can you find some paths of your own?
Function Machines
Age 7 to 11
Challenge Level
If the numbers 5, 7 and 4 go into this function machine, what numbers will come out?
The Clockmaker's Birthday Cake
Age 7 to 11
Challenge Level
The clockmaker's wife cut up his birthday cake to look like a clock face. Can you work out who received each piece?
All Seated
Age 7 to 11
Challenge Level
Look carefully at the numbers. What do you notice? Can you make another square using the numbers 1 to 16, that displays the same properties?
Sometimes We Lose Things
Age 7 to 11
Challenge Level
Well now, what would happen if we lost all the nines in our number system? Have a go at writing the numbers out in this way and have a look at the multiplications table.
Diagonal in a Spiral
Age 7 to 11
Challenge Level
Investigate the totals you get when adding numbers on the diagonal of this pattern in threes.
Magic Triangle
Age 7 to 11
Challenge Level
Place the digits 1 to 9 into the circles so that each side of the triangle adds to the same total.
Homes
Age 5 to 7
Challenge Level
There are to be 6 homes built on a new development site. They could be semi-detached, detached or terraced houses. How many different combinations of these can you find?
The Pied Piper of Hamelin
Age 7 to 11
Challenge Level
This problem is based on the story of the Pied Piper of Hamelin. Investigate the different numbers of people and rats there could have been if you know how many legs there are altogether!
Up and Down
Age 5 to 7
Challenge Level
Sam got into an elevator. He went down five floors, up six floors, down seven floors, then got out on the second floor. On what floor did he get on?
Big Dog, Little Dog
Age 5 to 7
Challenge Level
Woof is a big dog. Yap is a little dog. Emma has 16 dog biscuits to give to the two dogs. She gave Woof 4 more biscuits than Yap. How many biscuits did each dog get?
Follow the Numbers
Age 7 to 11
Challenge Level
What happens when you add the digits of a number then multiply the result by 2 and you keep doing this? You could try for different numbers and different rules.
Number Juggle
Age 7 to 11
Challenge Level
Fill in the missing numbers so that adding each pair of corner numbers gives you the number between them (in the box).
Journeys
Age 7 to 11
Challenge Level
Investigate the different distances of these car journeys and find out how long they take.
Number Squares
Age 5 to 11
Challenge Level
Start with four numbers at the corners of a square and put the total of two corners in the middle of that side. Keep going... Can you estimate what the size of the last four numbers will be?
Sending Cards
Age 7 to 11
Challenge Level
This challenge asks you to investigate the total number of cards that would be sent if four children send one to all three others. How many would be sent if there were five children? Six?
Doplication
Age 7 to 11
Challenge Level
We can arrange dots in a similar way to the 5 on a dice and they usually sit quite well into a rectangular shape. How many altogether in this 3 by 5? What happens for other sizes?
Magic Constants
Age 7 to 11
Challenge Level
In a Magic Square all the rows, columns and diagonals add to the 'Magic Constant'. How would you change the magic constant of this square?
Being Collaborative - Lower Primary Number
Age 5 to 7
Number problems for you to work on with others.
Calendar Patterns
Age 7 to 11
Challenge Level
In this section from a calendar, put a square box around the 1st, 2nd, 8th and 9th. Add all the pairs of numbers. What do you notice about the answers?
How Old?
Age 7 to 11
Challenge Level
Cherri, Saxon, Mel and Paul are friends. They are all different ages. Can you find out the age of each friend using the information?
Sept03 Sept03 Sept03
Age 7 to 11
Challenge Level
This number has 903 digits. What is the sum of all 903 digits?
X Is 5 Squares
Age 7 to 11
Challenge Level
Can you arrange 5 different digits (from 0 - 9) in the cross in the way described?
Marvellous Matrix
Age 7 to 11
Challenge Level
Follow the directions for circling numbers in the matrix. Add all the circled numbers together. Note your answer. Try again with a different starting number. What do you notice?
The 24 Game
Age 7 to 11
Challenge Level
There are over sixty different ways of making 24 by adding, subtracting, multiplying and dividing all four numbers 4, 6, 6 and 8 (using each number only once). How many can you find?
Escape from the Castle
Age 7 to 11
Challenge Level
Skippy and Anna are locked in a room in a large castle. The key to that room, and all the other rooms, is a number. The numbers are locked away in a problem. Can you help them to get out?
Digit Addition
Age 5 to 11
Challenge Level
Try out this number trick. What happens with different starting numbers? What do you notice?
Asteroid Blast
Age 7 to 11
Challenge Level
A game for 2 people. Use your skills of addition, subtraction, multiplication and division to blast the asteroids.
A Numbered Route
Age 7 to 11
Challenge Level
Can you draw a continuous line through 16 numbers on this grid so that the total of the numbers you pass through is as high as possible?
Number Tracks
Age 7 to 11
Challenge Level
Ben’s class were cutting up number tracks. First they cut them into twos and added up the numbers on each piece. What patterns could they see?
Children's Mathematical Graphics: Understanding the Key Concept
Age 5 to 7
In this article for teachers, Elizabeth Carruthers and Maulfry Worthington explore the differences between 'recording mathematics' and 'representing mathematical thinking'.
Numbered Cars
Age 7 to 11
Challenge Level
I was looking at the number plate of a car parked outside. Using my special code S208VBJ adds to 65. Can you crack my code and use it to find out what both of these number plates add up to?
How Much Did it Cost?
Age 7 to 11
Challenge Level
Use your logical-thinking skills to deduce how much Dan's crisps and ice-cream cost altogether.
Bundles of Cubes
Age 7 to 11
Challenge Level
Watch this animation. What do you notice? What happens when you try more or fewer cubes in a bundle?
NRICH is part of the family of activities in the Millennium Mathematics Project.