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  #### Resources tagged with Addition & subtraction similar to So It's Times!:
  
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  ### Scoring with Dice
  
  ##### Stage: 2 Challenge Level:
  
  I throw three dice and get 5, 3 and 2. Add the scores on the three dice. What do you get? Now multiply the scores. What do you notice?
  
  ### A Mixed-up Clock
  
  ##### Stage: 2 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?
  
  ### Abundant Numbers
  
  ##### Stage: 2 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?
  
  ### Number Tracks
  
  ##### Stage: 2 Challenge Level:
  
  Benâ€™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?
  
  ### Being Determined - Primary Number
  
  ##### Stage: 1 and 2 Challenge Level:
  
  Number problems at primary level that may require determination.
  
  ### Got it for Two
  
  ##### Stage: 2 Challenge Level:
  
  Got It game for an adult and child. How can you play so that you know you will always win?
  
  ### 2010: A Year of Investigations
  
  ##### Stage: 1, 2 and 3
  
  This article for teachers suggests ideas for activities built around 10 and 2010.
  
  ### Being Collaborative - Primary Number
  
  ##### Stage: 1 and 2 Challenge Level:
  
  Number problems at primary level to work on with others.
  
  ### Book Codes
  
  ##### Stage: 2 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?
  
  ### Zios and Zepts
  
  ##### Stage: 2 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?
  
  ##### Stage: 2 Challenge Level:
  
  Lolla bought a balloon at the circus. She gave the clown six coins to pay for it. What could Lolla have paid for the balloon?
  
  ### Rod Measures
  
  ##### Stage: 2 Challenge Level:
  
  Using 3 rods of integer lengths, none longer than 10 units and not using any rod more than once, you can measure all the lengths in whole units from 1 to 10 units. How many ways can you do this?
  
  ### Dice and Spinner Numbers
  
  ##### Stage: 2 Challenge Level:
  
  If you had any number of ordinary dice, what are the possible ways of making their totals 6? What would the product of the dice be each time?
  
  ### Throw a 100
  
  ##### Stage: 2 Challenge Level:
  
  Can you score 100 by throwing rings on this board? Is there more than way to do it?
  
  ### Super Shapes
  
  ##### Stage: 2 Short Challenge Level:
  
  The value of the circle changes in each of the following problems. Can you discover its value in each problem?
  
  ### Pouring the Punch Drink
  
  ##### Stage: 2 Challenge Level:
  
  There are 4 jugs which hold 9 litres, 7 litres, 4 litres and 2 litres. Find a way to pour 9 litres of drink from one jug to another until you are left with exactly 3 litres in three of the jugs.
  
  ### Make 100
  
  ##### Stage: 2 Challenge Level:
  
  Find at least one way to put in some operation signs (+ - x ÷) to make these digits come to 100.
  
  ### Bean Bags for Bernard's Bag
  
  ##### Stage: 2 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?
  
  ### Machines
  
  ##### Stage: 2 Challenge Level:
  
  What is happening at each box in these machines?
  
  ### On Target
  
  ##### Stage: 2 Challenge Level:
  
  You have 5 darts and your target score is 44. How many different ways could you score 44?
  
  ### Napier's Bones
  
  ##### Stage: 2 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?
  
  ### Penta Post
  
  ##### Stage: 2 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?
  
  ### Sending Cards
  
  ##### Stage: 2 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?
  
  ### The Pied Piper of Hamelin
  
  ##### Stage: 2 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
  
  ##### Stage: 2 Challenge Level:
  
  Where can you draw a line on a clock face so that the numbers on both sides have the same total?
  
  ### Hubble, Bubble
  
  ##### Stage: 2 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?
  
  ### The Puzzling Sweet Shop
  
  ##### Stage: 2 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?
  
  ### Sometimes We Lose Things
  
  ##### Stage: 2 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.
  
  ### Times
  
  ##### Stage: 2 Challenge Level:
  
  Which times on a digital clock have a line of symmetry? Which look the same upside-down? You might like to try this investigation and find out!
  
  ### Oranges and Lemons
  
  ##### Stage: 2 Challenge Level:
  
  On the table there is a pile of oranges and lemons that weighs exactly one kilogram. Using the information, can you work out how many lemons there are?
  
  ### Back to School
  
  ##### Stage: 2 Challenge Level:
  
  Mr. Sunshine tells the children they will have 2 hours of homework. After several calculations, Harry says he hasn't got time to do this homework. Can you see where his reasoning is wrong?
  
  ### A-magical Number Maze
  
  ##### Stage: 2 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!
  
  ### Rocco's Race
  
  ##### Stage: 2 Short Challenge Level:
  
  Rocco ran in a 200 m race for his class. Use the information to find out how many runners there were in the race and what Rocco's finishing position was.
  
  ### Amy's Dominoes
  
  ##### Stage: 2 Challenge Level:
  
  Amy has a box containing domino pieces but she does not think it is a complete set. She has 24 dominoes in her box and there are 125 spots on them altogether. Which of her domino pieces are missing?
  
  ### Doplication
  
  ##### Stage: 2 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?
  
  ### Calendar Calculations
  
  ##### Stage: 2 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?
  
  ### Four Goodness Sake
  
  ##### Stage: 2 Challenge Level:
  
  Use 4 four times with simple operations so that you get the answer 12. Can you make 15, 16 and 17 too?
  
  ##### Stage: 2 Challenge Level:
  
  Can you put plus signs in so this is true? 1 2 3 4 5 6 7 8 9 = 99 How many ways can you do it?
  
  ### The Clockmaker's Birthday Cake
  
  ##### Stage: 2 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?
  
  ### Sealed Solution
  
  ##### Stage: 2 Challenge Level:
  
  Ten cards are put into five envelopes so that there are two cards in each envelope. The sum of the numbers inside it is written on each envelope. What numbers could be inside the envelopes?
  
  ### Open Squares
  
  ##### Stage: 2 Challenge Level:
  
  This task, written for the National Young Mathematicians' Award 2016, focuses on 'open squares'. What would the next five open squares look like?
  
  ### Two Primes Make One Square
  
  ##### Stage: 2 Challenge Level:
  
  Can you make square numbers by adding two prime numbers together?
  
  ### Seven Square Numbers
  
  ##### Stage: 2 Challenge Level:
  
  Add the sum of the squares of four numbers between 10 and 20 to the sum of the squares of three numbers less than 6 to make the square of another, larger, number.
  
  ### The Deca Tree
  
  ##### Stage: 2 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.
  
  ### Dividing a Cake
  
  ##### Stage: 2 Challenge Level:
  
  Annie cut this numbered cake into 3 pieces with 3 cuts so that the numbers on each piece added to the same total. Where were the cuts and what fraction of the whole cake was each piece?
  
  ### How Much Did it Cost?
  
  ##### Stage: 2 Challenge Level:
  
  Use your logical-thinking skills to deduce how much Dan's crisps and ice-cream cost altogether.
  
  ### All Seated
  
  ##### Stage: 2 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?
  
  ### Shapes in a Grid
  
  ##### Stage: 2 Challenge Level:
  
  Can you find which shapes you need to put into the grid to make the totals at the end of each row and the bottom of each column?
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