What is the word or phrase?

Can you solve this tricky maths equation problem by replacing it? mark with the correct symbol?

19834 -----: 187
15921 -----: 153
17561 -----: 139
13734 -----: ???

Two friends were betting. One said to the other, "The coin will be flipped twenty times and each time the coin lands on the head, I will give you $2 and each time it lands on the tale, you will give me $3." After flipping the coin twenty times not a single penny was exchanged among them.

How many times did the coin land on heads?

If 1+9+8=1, what is 2+8+9?

Can you make four (4) nines (9) equal 100?

Can you count the number of blocks in the picture below?

John went to a parrot shop in Mexico, and the parrot owner told him that his parrot is so unique that he repeats everything he hears. John got excited and immediately bought the parrot. John went home and spoke many words, but the parrot does not repeat anything.
He went again to the parrot shop and complaint to the shopkeeper, but the shopkeeper never lied. Explain?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

There's one "sport" in which neither the spectators nor the participants know the score or the leader until the contest ends.

What is it?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.