I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

What is wrong in the below Picture?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

As shown in the image, the nine Dogs are square fenced. By constructing just two square fences can you make sure that two Dogs cannot meet each other without crossing the fence?

I am 5 letters long.
My first two tell you who I am
My first 3 could be a medicine
My last three reversed could be a young boy.
My 4th, 3rd and 2nd in that order could be a fruit drink.
If you have me you may hang me round your neck
WHAT AM I ?

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

The ages of a father and son add up to 66.
The father's age is the son's age reversed.
How old could they be?
(3 possible solutions).

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?