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Double Digit

Choose two digits and arrange them to make two double-digit numbers. Now add your double-digit numbers. Now add your single digit numbers. Divide your double-digit answer by your single-digit answer. Try lots of examples. What happens? Can you explain it?

Number Detective

Follow the clues to find the mystery number.

Six Is the Sum

What do the digits in the number fifteen add up to? How many other numbers have digits with the same total but no zeros?

More Less Is More

Age 7 to 14
Challenge Level

Sum-sum

42 + 16 < 55 + 35
Score = 42 + 16 = 58

With 1-8, the maximum score is more than 130 points

 

Take-take


Score = 55 - 35 = 20

With 1-8, the maximum score is more than 55 points

 

Take-sum


Score = 42 - 16 = 26

With 1-8, the maximum score is more than 70 points

 

Sum-take


Score = 12 + 24 = 36

With 1-8, the maximum score is more than 70 points