√2 = 1 + ...
11 1
11 1
12 2 2 2 2 2
125122970 &c.
2 5 12 29 70 169

Here it appears that

129 does not err by 1 ;
7070 × 169
consequently,99 or 100 - 1 is,
7070

considering the ease of the operation, a fair approximation. In fact, ⁹⁹/₇₀ is 1·4142857 ... the truth being 1·4142135 ...

The following is an additional example:

19 = 4 + ...
42 3 3 2 4 4 2
13 5 2 5 3 1 3
42 1 3 1 2 8 2 1 3 1 2, &c.
114514, &c.
2 3 11 14 39

APPENDIX IX.
ON SOME GENERAL PROPERTIES OF NUMBERS.