# DAY/DYDD 280: The Main Challenge

. . . is to arrive at the target number of 18 by adding together five numbers from 1 to 5, which can each be used any number of times in a calculation.

One way of making 18 is 5+5+5+2+1 (or 55521 to save time). Can you list the other EIGHT ways? The 7puzzle Challenge

The playing board of the 7puzzle game is a 7-by-7 grid of 49 different numbers, ranging from up to 84.

The 3rd & 5th rows contain the following fourteen numbers:

6   7   13   16   21   25   36   42   45   50   66   80   81   84

What is half of the highest prime number on the list? The Factors Challenge

Which FOUR of the following numbers are NOT factors of 280?

2    4    6    8    10    12    14    16    18    20 The Mathematically Possible Challenge

Using 27 and 10 once each, with + – × ÷ available, which are the only THREE numbers it is possible to make from the list below?

8    16    24    32    40    48    56    64    72    80

#8TimesTable The Target Challenge

Can you arrive at 280 by inserting 7, 8, 9, 10 and 11 into the gaps below?

•  ◯×◯×◯÷(◯–◯) = 280   