From the BEATCALC
mailing list:
a weekly service from B. Lee Clay,
archived here by the Math Forum.
To subscribe to the BEATCALC mailing list,
write to BEATCALC@aol.com.
Squaring special numbers (1 and
repeating 6's)
Choose a number with a 1 and repeating 6's.
The square is made up of:
first digits: 2 & one fewer 7 than repeating 6's
next digits: same number of 5's as repeating 6's
last digit: 6
Example:
If the number to be squared is 1666:
The square has:
first digits: 2 and one fewer
7 than 6's 2
7 7
next digits: same number of 5's
as 6's
5 5 5
last digit: 6
6
So 1666 x 1666 = 2775556.
See the pattern?
If the number to be squared is 166666:
The square has:
first digits: 2 and one fewer
7 than 6's 2
7 7 7 7
next digits: same number of 5's
as 6's
5 5 5 5 5
last digit: 6
6