7 is the module of the week, so the integer multiple of 7 is 0. After 28 days, it will be Wednesday. After 43 days, the module will be 43-6x7= 1. After 43 days, it will be Wednesday plus one, which will be Thursday.

Starting today, 14 is Sunday, and 3 1 day is Wednesday.

There are many formulas for this problem (two general formulas and some piecewise formulas), the most famous one is Zeiler's formula, that is, w = y+[y/4]+[c/4]-2c+[26 (m+1)1+d.

The origin of the month:

These names originated in Babylon, Cuba. In the 7th and 6th centuries BC, the Babylonians had a weekly system. They divide a month into four weeks, and each week has seven days, which is a week. Babylonians built seven-star altars to worship the stars. The seven-star altar is divided into seven layers, and each layer has a star god. There are seven gods from top to bottom: sun, moon, fire, water, wood, gold and earth.

God is in charge of one day of the week, so he sacrifices to one god every day, and every day is named after one god: Chamakh, the sun god, is in charge of Sunday, Sin, the moon god, is in charge of Monday, and Nelga, the Mars god, is in charge of Tuesday.