What is the next number in this matchsticks series riddle?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

I’m tall when I’m young, and I’m short when I’m old. What am I?

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

John is looking at Jenifer, but Jenifer is looking at Jacob. John is married, but Jacob is not.

Is a married person looking at an unmarried person ?

Identify the next two numbers in this series.

101, 112, 131, 415, 161, 718, ???, ???

There was once a troop of 5 elves. The 5 elves were very dedicated on finding the magical treasure of 1000 coins. However, being elves, they were super geniuses, very greedy and they did not hesitate in taking lives of other elves. The 5 elves were named Aye, Bee, Cee, Dee and Ee, ranked from high to low respectively, from Aye to Ee. One fine day, their efforts brought results and they found 1000 coins. Now they had to split it in between them as per their ranks. The lowest ranked elf has to make the proposal. If the proposal is accepted by majority, it is agreed, or the suggesting elf is killed.

What proposal should elf Ee make ?

You need to remove two matchsticks to make the below equation true. Can you do it ?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?