Nice and Easy

Purpose:

In this game students are required to double and halve two factors to make a number sentence that is easier to calculate.

In doing this the students realise the product remains unchanged.

You Need:

2 players

A nice and Easy Game Board

2 dice numbered (15, 15, 25, 35, 45, 45) and ( 6, 8, 12, 14, 16, 18)

15 counters a different colour for each player

To Play:

The aim is to arrange 3 counters adjacently in a horizontal, vertical or diagonal line

  • The first player rolls the dice
  • The player says the multiplication sentence represented by the dice, then doubles one factor and halves the other to figure out an equivalent sentence
  • The player states the product before covering the equivalent sentence on the game board. If the multiplication sentence is already covered the player misses that turn

Example: Lincoln rolls 35 and 16. He says 35 times 16 is the same as 70 times 8. 70 times 8 is 560 and he puts his counter on 70x8

  • The next player has a turn
  • The first player to make three adjacent counters is the winner

During the Game

  • Ask the children to explain the strategies they are using once they have worked out the equivalent number sentence eg 35 x 16 is the same as 70 x 8? By…
  • Knowing 7x8 = 56 so 10 x 7 x 8 = 560
  • Doubling 70 then doubling and doubling again
  • Knowing 70x10 = 700 so 70 x 8 must be 140 less

After the Game

  • What other number sentences could you use the doubling and halving strategy for? Make some up?
  • What numbers does this strategy work best for?
  • Play Nice and Easy 2 - say the equivalent number sentence – cover the answer

Nice and Easy 1

30x3 / 50x3 / 70x3 / 90x3
30x4 / 50x4 / 70x4 / 90x4
30x6 / 50x6 / 70x6 / 90x6
30x7 / 50x7 / 70x7 / 90x7
30x8 / 50x8 / 70x8 / 90x8
30x9 / 50x9 / 9
70x9 / 90x9

Before the game

See Cut and Paste Pg 25 Book 6 Teaching Multiplication and Division

Before playing the game students need exposure to the doubling and halving strategy

Show the children the happy face array and ask them to write a number sentence to show what they see (15 x 6)

Nice and Easy 2

200 / 450 / 420 / 280
810 / 120 / 270 / 490
180 / 630 / 90 / 720
240 / 630 / 300 / 210
150 / 360 / 350 / 560
540 / 400 / 270 / 210