Replace the question mark with the correct number below.

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

You are given with the following sum. Each of the letters can be decoded as a digit. If we tell you that D = 5, then can you solve it entirely?

DONALD
+GERALD
=ROBERT

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

What is the end of everything?

John and Jacob are playing bets. John gives $10 to Jacob and Jacob deals four cards out of a normal 52-card deck which are chosen by him completely randomly. Jacob keeps them facing down takes the first card and shows it to John. John has a choice of either keeping it or looking at the second card. When the second card is shown to him, he again has the choice of keeping or looking at the third which is followed by the third card as well; only if he does not want the third card, he will have to keep the fourth card.

If the card that John is choosing is n, Jacob will give it to him. Then the cards will be shuffled and the game will be played repeatedly. Now you might think that it all depends on chance, but John has come up with a strategy that will help him turn the favor in his odds.

Can you deduce the strategy of John?

While preparing the table for dinner, wife came up with an idea to tease his mathematician husband. She asked her husband to pick nine toothpicks and make ten without breaking any toothpick.

The husband was also smart and did it within seconds. How ?

Arrange the numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9 above and below the division line in a manner that the thus formed fractions equal to 1/3.

(You can use one number only once)

John can place six large boxes or nine small boxes into a carton.

Can you find out in how many cartons can he place sixty-six boxes in total?