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� Now suppose we want the digit sum of 417.
Adding 4, 1 and 7 gives 12.
But as 12 is a 2-figure number we add its digits
to get 3 (1 + 2 = 3).
We could write 417 = 12 = 3.
� And so 737 = 17 = 8.
www.classtopper.com
We simply add the digits in the number and add
again if necessary.
This is simple and one of its uses is in checking
sums, as we will see.
Find the digit sum for each of the following:
1) 85 2) 38 3) 77 4) 99 5) 616 6) 7654
25
All things that can
be known have number;
for it is not possible
that without
numbers anything
can be either conceived
or known.
PHILOLAUS