Why is Saturday stronger than Monday?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

I add 5 to 9 and get 2. The answer is correct, so what am I?

Can you spot what's wrong with the following sentence?

PETER WAS ANGRY AT
HIMSELF BECAUSE HE
ACCIDENTALLY LEFT THE
THE KEYS TO HIS CAR
AT HIS FRIEND'S HOUSE.

The day after tomorrow will be three days before Tuesday. Can you find out what is today?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

Can you place three balls such that the equation shown in the picture holds true?

You can hear me, but you can't touch or see me.

What am I?

I am the largest in my family of fifty.
The youngest of our family lives separately from the rest of the family and so do I.
I am regarded as harsh and tough.
I am so large, you cut me in two equal halves,
each half would still be larger than the second largest member of the family.
Who am I?

You have to fill the below given grid in a manner that every row and column contains the digits 1 to 6. Also, make sure that the squares that are connected with each other must contains the same digit.