The Between Decimals Game: Solution

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Jenny, Sarah and Jason play a game. Jenny and Sarah choose a decimal and Jason tries to find a decimal that is between Jenny’s and Sarah’s decimals on the number line.

If Jenny chooses 0.012 and Sarah chooses 0.12, give some suggestions for what decimals Jason could choose.
 
Solution
 
There are very many decimals that Jason could have chosen. To see some of these, first recall that 0.012 = 12 thousandths and 0.12 = 12 hundredths or 120 thousandths. So he is looking for a decimal that is more than 12 thousandths and less than 120 thousandths. 
 
Clearly he could choose 13 thousandths (0.13), or 14 thousandths (0.14) or 15... or anything up to 119 thousandths (0.119).
 
If he wanted to use more decimal places he could have chosen 0.0121 or any other decimal with the first two places less than 0.12.
 
Extension
 
How many more decimals can you find that Jason could have chosen?
 
You might also like to play this game with two friends.