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21 st
Activity Century #Computational Thinking
Skills

Finding mystery Numbers
Perform this activity in pairs.

Each player thinks of a 5-digit number and creates an index card by writing clues for
finding the “Mystery Number". mystery Number

For example: TTh Th H T O

Clue 1: The digit in the tens place is 0.
Clue 2: The digit 5 has a place value of 50,000.

Clue 3: The digit in the hundreds place is the product of 3 and 2.
Clue 4: The second digit from the left is 7.

Clue 5: The sum of the digits of the number is 26.

Then they will exchange index cards and find the number. The player who writes the
“Mystery Number" first will get a point.

Repeat the activity for 3 or 5 rounds. The player with more points will be declared the winner.

rOuNDINg NumberS

Read out the following interesting facts.

Lightning strikes the A hummingbird’s The Eiffel Tower has We take about
Earth about 6,000 heart beats about about 1,700 steps. 23,000 breaths
times every minute. 1,000 times in a every day.
minute.

The facts mentioned above do not give exact numbers (figures). They give only
approximate values. The actual figures could be slightly higher or lower than the
numbers mentioned above. Such numbers are called rounded numbers.

18 Mathematics 4