# Number Sense

(e.g. 2 +1 +2 = 3)

1. Twelve pigs were eating a farmer's groundnuts when he came out and shot dead one of them. How many remained in the field?

2. One cat walked in front of two cats. One cat walked behind two cats. One cat walked between two cats. How many were there?

A popular Hindi version of this is

3. A crab is trying to climb a glass pane 30 cm high. It climbs 10 cm in 5 minutes and then rests for 5 minutes during which it slips back 5 cm. How much time will the crab take to reach the top?

4. How many times does the digit 9 appear from 1 to 100?

5. Every morning at 6, a ship leaves Tokyo for New
York and at the same time, a ship leaves New York for Tokyo. It takes 10 days to
complete the trip either way. If a New York bound ship starts from Tokyo on 15th
of a month, how many Tokyo bound ships will it meet by the time it reaches New York?

(Ignore difference of timings between New York and Tokyo.)

6. A zoo has some birds and some beasts. There are 30 heads and 100 feet. Can you tell the number of birds and beasts?

7. (My grandpa asked me this) You can buy 20 sparrows for a rupee, while a pigeon costs one rupee and a parrot costs five rupees. You want to purchase 100 birds in 100 rupees so that you have birds of each variety. How can you do this?

8. A rich Arab having 23 prize camels died. His will stated that the eldest son Ahab was to have half of the camels. The second son Aziz was to have a third, and the youngest Abdul was to have an eighth share. The sons soon realized that they couldn't divide 23 camels amongst them without slaughtering some of the camels. However, their wise uncle loaned them one of his own camels and easily solved the problem. Can you figure it out?