Author Archives: 7puzzle

The Main Challenge Fill the 15 gaps below with the numbers 1-15, once each, so all five lines work out: ◯   +   ◯   =   ◯ ◯   +   ◯   =   ◯ ◯   + … Continue reading →

The Main Challenge Here’s a mini-Mathelona challenge where you must place the eight digits 0, 1, 1, 2, 2, 2, 3 and 4 into the eight gaps so both lines work out arithmetically: ◯  +  ◯   =    4   … Continue reading →

The Main Challenge Three unique digits from 1-9 must be used in a particular way to arrive at a specified target number. The rule is to multiply two numbers together, then either add or subtract the third number, so you arrive at … Continue reading →

The Main Challenge Read the following five clues:  I am a 2-digit number,  My 1st digit is bigger than my 2nd digit,  I am less than 50,  I am an odd number,  I am not a prime number. and work … Continue reading →

The Main Challenge Can you make all three lines work out arithmetically by placing the numbers 1, 2, 3, 4, 5, 6, 10, 11 and 12 into the nine gaps below? ◯   +   ◯   =   ◯◯   +   ◯ … Continue reading →

The Main Challenge Here’s a 10-step number trail involving all four arithmetical operations together with the numbers 1, 2 and 3. Starting with 10, carry out the following steps: add 2 ×1 ÷3 –2 multiply by 3 +1 subtract 3 divide … Continue reading →

The Main Challenge Using each of the decimal numbers 0.1, 0.2, 0.3 and 0.4 once only, and with the four arithmetical operations + – × and ÷ available, show how you can arrive at the target answer of 7. The 7puzzle Challenge The playing board … Continue reading →

The Main Challenge Can you make all four lines work out arithmetically by replacing the 16 ◯’s with the digits 0-9 in our latest Mathelona challenge? ◯  +  ◯   =    10    =   ◯  +  ◯ ◯  +  ◯   … Continue reading →

The Main Challenge Can you arrive at the target number 81 by using the five numbers 1, 2, 3, 4 and 5 exactly once each, and with + – ×  ÷ available? The 7puzzle Challenge The playing board of the 7puzzle game is a … Continue reading →

The Main Challenge From the following list of eighteen numbers, eliminate all square numbers, multiples of 8, factors of 60 and prime numbers. 3  4  7  10  11  15  16  17  24  27  30  32  36  48  49  54  56  … Continue reading →