When we see 2 but call 10?

Which English verb becomes past tense just by rearranging the letters?

Using eight eights and addition only, can you make 1000?

What is black when you buy it, red when you use it, and gray when you throw it away?

John is the son of Jacob.
So,
Jacob is the_____of John's father?

What word begins and ends with an E, but has only one letter?

Let's play a word game. Following are some meaningless words that can be completed by adding random letters on either side of the word.

For example, the word "rdo" can be formed into "pardon".

Using the same technique, can you complete the given words?
ecalc
airb
rinci
tibac
uidel
gorit
igna
eyho

Which tank will fill first?

Today, I celebrated my 32nd birthday but I was born in 1972.
How is this possible?

A time long back, there lived a king who ruled the great kingdom of Trojan House. As a part of the renovation of the kingdom to meet future security needs, he asked his chief architect to lay down a new play in a manner that all of his 10 castles are connected through five straight walls and each wall must connect four castles together. He also asked the architect that at least one of his castles should be protected with walls. The architect could not come up with any solution that served all of King's choices, but he suggested the best plan that you can see in the picture below. Can you find a better solution to serve the king's demand?