# Calendar

**This trick must be used when we need to calculate previous date from the given date.**

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Q1.) What was the day of the week on **17 January 1883**?

### STEP 1 :

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First of all substract 1 with the year

1883 - 1 = 1882

### STEP 2 :

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Divide the year with 400 to check the number of leap year

1882 / 400 = 282

### STEP 3:

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100 years = 5 odd days so

282 year & 1 Jan to 17 January 1883

2 * 100 = 2 * 5 = 10 odd day

### STEP 4:

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Now again check leap year

82 year = 82 / 4 = 20 leap year

and subtract the leap year with 82 to calculate ordinary year

82 year = 20 leap year + 62 odinary year

### STEP 5:

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As we know

1 leap year = 2 odd day

1 ordinary year = 1 odd day

20 * 2 + 62 * 1 = 102

Now divide the total days with 7 and reminder will be odd days

102 / 7 = 4 odd days

### STEP 6:

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1 Jan to 17 January 1883

Number of Days in 1883 | ||

Jan | 16 | |
---|---|---|

Total No. of Days | 16 |