sentences:  The third and fourth digits (xx00 through xx17) similarly indicate the number of tens of degrees of longitude of the 'minimum' square boundary, nearest to the Prime Meridian.By way of illustration, the square 1000 thus extends from 0°N to 10°N, 0°E to 10°E, and the square 7817 from 80°N to 90°N, 170°W to 180°W, adjacent to the major portion of the International Date Line.In this manner, reverse-engineering (decoding) the relevant square boundaries from any particular WMO Square identifier is straightforward, in contrast to some other similar systems e.g.