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Add Zeller's Congruence Algorithm in Math (#996)

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	`1`	`+// Zeller's Congruence Algorithm finds the day of the week from the Gregorian Date. Wikipedia: https://en.wikipedia.org/wiki/Zeller%27s_congruence`
	`2`	`+export const zellersCongruenceAlgorithm = (day, month, year) => {`
	`3`	`+ if (typeof day !== 'number' \|\| typeof month !== 'number' \|\| typeof year !== 'number') {`
	`4`	`+ throw new TypeError('Arguments are not all numbers.')`
	`5`	`+ }`
	`6`	`+ const q = day`
	`7`	`+ let m = month`
	`8`	`+ let y = year`
	`9`	`+ if (month < 3) {`
	`10`	`+ m += 12`
	`11`	`+ y -= 1`
	`12`	`+ }`
	`13`	`+ day =`
	`14`	`+ (q + Math.floor(26 * (m + 1) / 10) + (y % 100) + Math.floor((y % 100) / 4) + Math.floor(Math.floor(y / 100) / 4) + (5 * Math.floor(y / 100))) %`
	`15`	`+ 7`
	`16`	`+ const days = [`
	`17`	`+ 'Saturday',`
	`18`	`+ 'Sunday',`
	`19`	`+ 'Monday',`
	`20`	`+ 'Tuesday',`
	`21`	`+ 'Wednesday',`
	`22`	`+ 'Thursday',`
	`23`	`+ 'Friday'`
	`24`	`+ ]`
	`25`	`+ return days[day]`
	`26`	`+}`

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	`1`	`+import { zellersCongruenceAlgorithm } from '../ZellersCongruenceAlgorithm'`
	`2`	`+`
	`3`	`+function testZeller (day, month, year, expected) {`
	`4`	`+ test('Testing on ' + day + '/' + month + '/' + year, () => {`
	`5`	`+ expect(zellersCongruenceAlgorithm(day, month, year)).toBe(expected)`
	`6`	`+ })`
	`7`	`+}`
	`8`	`+`
	`9`	`+test('Testing on this/should/throw', () => {`
	`10`	`+ expect(() => {`
	`11`	`+ zellersCongruenceAlgorithm('this', 'should', 'error')`
	`12`	`+ }).toThrowError(new TypeError('Arguments are not all numbers.'))`
	`13`	`+})`
	`14`	`+testZeller(25, 1, 2013, 'Friday')`
	`15`	`+testZeller(26, 1, 2013, 'Saturday')`
	`16`	`+testZeller(16, 4, 2022, 'Saturday')`
	`17`	`+testZeller(25, 4, 2022, 'Monday')`

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