The number that does not have a reciprocal is?

What is the next number in the sequence? 1000 1001 1010 1011 1100 ...

Where should parentheses be added to make the following expression true? 2 * 1 + 1 + 3 * 1 + 1 + 1 = 11

In how many of the following lines are the two columns identical? #45dF$ #45dF$ &RtaVl &RtoVI Ypa$D Ypa$D 6TYO! 6TYO!

3 * 3 * 3 + 3 * 3 =

In how many of the following lines are the two numbers exactly the same? 852390 852390 123457 1234567 23456 23456

If every alternative letter starting from B of the English alphabet is written in small letter, rest all are written in capital letters, how the month “ September” be written:

Event A and event B take a variable amount of time to complete. Event A and event B can both start before the other completes. If event A can not complete until event B completes and event B can not complete until event A completes, which of these statements are true?

What comes next in the following sequence? 2, 7, 14, 23, 34, 47 ...

In how many of the four lines below does a number appear more than once without being the first or last number on the line? 23345 11256 56798 89878

Given the following, what comes next in the sequence? 4, 16, 36, 64, 100, ...