# DAY 329: The Main Challenge

. . . is a Mathelona number puzzle where you must solve all four lines arithmetically by filling the 16 gaps below with digits 0-9.

Each digit 0-9 can only be inserted a maximum of TWICE in the whole puzzle:

◯  +  ◯   =     5     =   ◯  +  ◯
◯  +  ◯   =     3     =   ◯  –  ◯
◯  +  ◯   =    10    =   ◯  ×  ◯
◯  +  ◯   =     1     =   ◯  ÷  ◯

If you enjoyed this, click Mathelona for details of my number puzzle pocket book. The 7puzzle Challenge

The playing board of the 7puzzle game is a 7-by-7 grid containing 49 different numbers, ranging from 2 up to 84.

The 5th & 7th columns contain the following fourteen numbers:

5   8   9   11   14   18   24   25   28   32   44   50   66   84

Which THREE numbers above 11 each become a multiple of 7 when 11 is subtracted from them? The Factors Challenge

Which is the ONLY number below that is a factor of 329?

3    5    7    9    11    13    15    17 The Mathematically Possible Challenge

Using 56 and 12 once each, with + – × ÷ available, which is the ONLY number it is possible to make from the list below?

1    4    9    16    25    36    49    64    81    100

#SquareNumbers The Target Challenge

Can you arrive at 329 by inserting 1, 4, 9, 16 and 25 into the gaps below?

•  ◯×◯×(◯+◯)+◯ = 329   