New teaser:

I have 100 sweets in 5 bowls.

1st and 2nd = 52

2nd and 3rd = 43

3rd and 4th = 34

4th and 5th = 30

How many are in each bowl?

Previous problem:

What is X?

3       8                     9     132                  14     X

56     6                    12     72                 21   182

 Answer: 420

Opposite numbers are obtained by multiplying the smaller number by one less than itself. In the first square 3 x 2 = 6 and 8 x 7 = 56, in the second 9 x 8 = 72, etc, so in the thirs it is 21 x 20 = 420.