שבת לחמקשש = 740 =
The Gematria of Mekoshesh equals Shabbos +38 .The Mekoshesh kept shabbos by
refraining from 38 melochos. One melocho, he didn’t refrain from, and was mechallel
There is a Machloko in the Gemoro which one it was. a) Tolesh - b) Meamer -c) Mavir daled amos.