Author Archives: 7puzzle

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 placing the digits 0-9 into the 16 gaps 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 →

The Main Challenge Using the three numbers 4, 4 and 4 once each, with + – × ÷ available, there are just SIX target numbers from 1-30 that are mathematically possible to achieve.  Can you find them? The 7puzzle Challenge The playing board … Continue reading →

The Main Challenge Using the three numbers 1, 2 and 4 just once each, with + – × ÷ available to you, what is the lowest positive number it is NOT possible to make? The 7puzzle Challenge The playing board of the 7puzzle game is a … Continue reading →

The Main Challenge Solve all four lines arithmetically by filling the 16 gaps below with digits 0-9, but each digit must only be inserted a maximum of TWICE in the whole challenge: ◯  +  ◯   =     8 … Continue reading →

The Main Challenge Find the sum of the numbers that remain after eliminating multiples of 3, 5 and 7 from all the odd numbers between 10 and 40. The 7puzzle Challenge The playing board of the 7puzzle game is a 7-by-7 grid containing 49 different … Continue reading →

The Main Challenge You have been given the task of manually numbering a 100-page document from 1 to 100. How many digits will you write altogether? The 7puzzle Challenge The playing board of the 7puzzle game is a 7-by-7 grid containing 49 … Continue reading →