When my father was 31 I was 8. Now he is twice as old as me. How old am I?
The difference in age is 23 years, so the son must be 23 if the father is twice as old as he.
What is the square root of 169?
1 – 1 ÷ 1 + 1 – 1 ÷ 1 = ?
You have 1000, add 40, add 1000, add 30, add another 1000, add 20, add 1000 again, and finally add 10. What is the result?
Complete the following series: 7,645 - 5,764 - 4,576 - ????
If seven people meet each other and each shakes hands only once with each of the others, how many handshakes will there have been?
The first person shakes the hand of 6 others, the second person shakes the hand of 5 remaining people, the third person shakes the hand of 4 remaining people, the fourth person shakes the hand of 3 remaining people, the 5th person shakes the hand of 2 remaining people and the sixth person shakes the hand of 1 remaining person. 6+5+4+3+2+1=21
There are 10 red socks and 10 blue socks, you are in pitch darkness and you're looking for 2 matching socks. What is the smallest number of socks you must take?