Day of the date


Day of the Week:
January has 31 days. It means that every date in February will be 3 days later than the same date in January(28 is 4 weeks exactly). The below table is calculated in such a way. Remember this table which will help you to calculate.

January

0

February

3

March

3

April

6

May

1

June

4

July

6

August

2

September

5

October

0

November

3

December

5
]


Step1: Ask for the Date. Ex: 23rd June 1986
Step2: Number of the month on the list, June is 4.
Step3: Take the date of the month, that is 23
Step4: Take the last 2 digits of the year, that is 86.
Step5: Find out the number of leap years. Divide the last 2 digits of the year by 4, 86 divide by 4 is 21.
Step6: Now add all the 4 numbers: 4 + 23 + 86 + 21 = 134.
Step7: Divide 134 by 7 = 19 remainder 1.
The reminder tells you the day.


Sunday

0

Monday

1

Tuesday

2

Wednesday

3

Thursday

4

Friday

5

Saturday

6

Answer: Monday

 

Square Number


Tips 1: 2 Digit Number which ends in 5
Step1: Multiply the first digit of number, with the next to its number. Ex: 35 is the number you want to square. 3 x 4 = 12
Step2: Finally add 25 at the end of the result.

Answer: 1225

Tips 2: Any 2 Digit Number
Ex: 47
Step1: Look for the nearest 10 boundary.
3 from 47 to 50
Step2: Since we went up 3 to 50, now go down 3 from 47 to 44.
Step3: Now mentally multiply 44 x 50 = 2200 - 1st answer.
Step4: 47 is 3 away from the 10 boundary 50, Square 3 as 9 - 2nd answer.
Step5: Add the first and second answer, 2200 + 9

Answer: 2209

 

 

                                Divisibility
This is a funny tricky play of maths. Checking Divisibility

 

Divisibility by 16:
How to check a number is divisible by 16?
It is very simple, first check the last four digits of the number is divisible by 16, then the number will be divisible by 16.

Examples:
Is the number 104661904 divisible by 16?
Take the last four digits in the given number,
last four digit is 1904, which is divisible by 16,
so 104661904 is divisible by 16.

Is the number 321564341 divisible by 16?
The last four digit of the number is 4341, which is not divisible by 16,
so the number 321564341 is not divisible by 16.

Divisibility by 24:
How to check a number is divisible by 24?
It is very simple, check the number is divisible by 3 and 8, if it is divisible by both, then clearly the number is divisible by 24.

Examples:
Is the number 210103512 divisible by 24?
First check the number is divisible by 3,
2 + 1 + 0 + 1 + 0 + 3 + 5 + 1 + 2 = 15
15 is divisible by 3, so the number is also divisible by 3.
Then check the number is divisible by 8 also,
The last three digit of the number is 512.
512 is divisible by 8, so the number is also divisible by 8.
The number 210103512 is divisible both by 3 and 8, so it is divisible by 24.

Is the number 674665413 divisible by 24?
6 + 7 + 4 + 6 + 6 + 5 + 4 + 1 + 3 = 42.
42 is divisible by 3, so the number is also divisible by 3.
Now check the number is divisible by 8 also,
The last three digit of the number is 413.
413 is not divisible by 8, so the number is not divisible by 8
The number 674665413 is divisible only by 3 and not by 8, so it is not divisible by 24.

Divisibility by 40:
How to check a number is divisible by 40?
It is very simple, check the number is divisible by 5 and 8, if it is divisible by both, then clearly the number is divisible by 40.

Examples:
Is the number 31948541800 divisible by 40?
First check the number is divisible by 5,
Check the units digit in the given number.
unit digit is 0, so the number is also divisible by 5.
Then check the number is divisible by 8 also,
The last three digit of the number is 800.
800 is divisible by 8, so the number is also divisible by 8.
The number 31948541800 is divisible both by 5 and 8, so it is divisible by 40.

Is the number 745413930 divisible by 40?
Check the units digit in the given number.
unit digit is 0, so the number is also divisible by 5.
Now check the number is divisible 8 also,
The last three digit of the number is 930.
930 is not divisible by 8, so the number is not divisible by 8
The number 745413930 is divisible only by 5 and not by 8, so it is not divisible by 40.

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