DAY 280:

The Main Challenge

. . . is to arrive at the target number of 18 by adding together exactly five numbers.  You are limited to using the digits 1 to 5 but these can be used any number of times in each calculation.

One way of making 18 is 5+5+5+2+1 (or 55521 to save time); can you list the other SIX 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

Answers can be found here.

Click Paul Godding for details of online maths tuition.

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