Other tags that relate to Starfish Spotting
Investigations. Addition & subtraction. Comparing and Ordering numbers. Factors and multiples. Combinations. Working systematically. Trial and improvement. Generalising. Games. Multiplication & division.There are 203 results
Broad Topics > Calculations and Numerical Methods > Addition & subtraction
Being Collaborative - Lower Primary Number
Age 5 to 7
Number problems for you to work on with others.
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?
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?
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?
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?
Twizzle's Journey
Age 5 to 7 Challenge Level:
Twizzle, a female giraffe, needs transporting to another zoo. Which route will give the fastest journey?
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?
Being Resourceful - Primary Number
Age 5 to 11 Challenge Level:
Number problems at primary level that require careful consideration.
Street Sequences
Age 5 to 11 Challenge Level:
Investigate what happens when you add house numbers along a street in different ways.
Napier's Bones
Age 7 to 11 Challenge Level:
The Scot, John Napier, invented these strips about 400 years ago to help calculate multiplication and division. Can you work out how to use Napier's bones to find the answer to these multiplications?
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.
Worms
Age 7 to 11 Challenge Level:
Place this "worm" on the 100 square and find the total of the four squares it covers. Keeping its head in the same place, what other totals can you make?
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?
Robot Monsters
Age 5 to 7 Challenge Level:
Use these head, body and leg pieces to make Robot Monsters which are different heights.
Here to There 1 2 3
Age 5 to 7 Challenge Level:
Move from the START to the FINISH by moving across or down to the next square. Can you find a route to make these totals?
Domino Join Up
Age 5 to 7 Challenge Level:
Can you arrange fifteen dominoes so that all the touching domino pieces add to 6 and the ends join up? Can you make all the joins add to 7?
Ring a Ring of Numbers
Age 5 to 7 Challenge Level:
Choose four of the numbers from 1 to 9 to put in the squares so that the differences between joined squares are odd.
Place Value as a Building Block for Developing Fluency in the Calculation Process
Age 5 to 11
This article for primary teachers encourages exploration of two fundamental ideas, exchange and 'unitising', which will help children become more fluent when calculating.
More Playing with Number Lower Primary
Age 5 to 7
Some additional activities to develop children's understanding of addition and subtraction of number through playing with number.
The Amazing Splitting Plant
Age 5 to 7 Challenge Level:
Can you work out how many flowers there will be on the Amazing Splitting Plant after it has been growing for six weeks?
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.
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.
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.
Sisters and Brothers
Age 7 to 11 Challenge Level:
Cassandra, David and Lachlan are brothers and sisters. They range in age between 1 year and 14 years. Can you figure out their exact ages from the clues?
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?
Zios and Zepts
Age 7 to 11 Challenge Level:
On the planet Vuv there are two sorts of creatures. The Zios have 3 legs and the Zepts have 7 legs. The great planetary explorer Nico counted 52 legs. How many Zios and how many Zepts were there?
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?
Bean Bags for Bernard's Bag
Age 7 to 11 Challenge Level:
How could you put eight beanbags in the hoops so that there are four in the blue hoop, five in the red and six in the yellow? Can you find all the ways of doing this?
On Target
Age 7 to 11 Challenge Level:
You have 5 darts and your target score is 44. How many different ways could you score 44?
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.
Hubble, Bubble
Age 7 to 11 Challenge Level:
Winifred Wytsh bought a box each of jelly babies, milk jelly bears, yellow jelly bees and jelly belly beans. In how many different ways could she make a jolly jelly feast with 32 legs?
Penta Post
Age 7 to 11 Challenge Level:
Here are the prices for 1st and 2nd class mail within the UK. You have an unlimited number of each of these stamps. Which stamps would you need to post a parcel weighing 825g?
Spell by Numbers
Age 7 to 11 Challenge Level:
Can you substitute numbers for the letters in these sums?
A Mixed-up Clock
Age 7 to 11 Challenge Level:
There is a clock-face where the numbers have become all mixed up. Can you find out where all the numbers have got to from these ten statements?
One Wasn't Square
Age 7 to 11 Challenge Level:
Mrs Morgan, the class's teacher, pinned numbers onto the backs of three children. Use the information to find out what the three numbers were.
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!
Clock Face
Age 7 to 11 Challenge Level:
Where can you draw a line on a clock face so that the numbers on both sides have the same total?
The Puzzling Sweet Shop
Age 7 to 11 Challenge Level:
There were chews for 2p, mini eggs for 3p, Chocko bars for 5p and lollypops for 7p in the sweet shop. What could each of the children buy with their money?
Throw a 100
Age 7 to 11 Challenge Level:
Can you score 100 by throwing rings on this board? Is there more than way to do it?
Digit Addition
Age 5 to 11 Challenge Level:
Try out this number trick. What happens with different starting numbers? What do you notice?
Zargon Glasses
Age 7 to 11 Challenge Level:
Zumf makes spectacles for the residents of the planet Zargon, who have either 3 eyes or 4 eyes. How many lenses will Zumf need to make all the different orders for 9 families?
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?
Build it up More
Age 7 to 11 Challenge Level:
This task follows on from Build it Up and takes the ideas into three dimensions!
Developing Number Fluency - What, Why and How
Age 5 to 11
In this article for primary teachers, Lynne McClure outlines what is meant by fluency in the context of number and explains how our selection of NRICH tasks can help.
Dot Card Games
Age 3 to 7
These games devised by Jenni Way use dot cards which will help children see the structure of numbers 1-6 and give them confidence as they begin to add and subtract these numbers.
The Dice Train
Age 7 to 11 Challenge Level:
This dice train has been made using specific rules. How many different trains can you make?
NRICH is part of the family of activities in the Millennium Mathematics Project.