### There are 7 results

Broad Topics >

Calculations and Numerical Methods > Mental addition & subtraction

##### Age 11 to 14 Challenge Level:

Who said that adding, subtracting, multiplying and dividing couldn't be fun?

##### Age 7 to 14 Challenge Level:

Can you spot the similarities between this game and other games you know? The aim is to choose 3 numbers that total 15.

##### Age 14 to 16 Challenge Level:

Use the differences to find the solution to this Sudoku.

##### Age 7 to 16 Challenge Level:

Place the numbers 1, 2, 3,..., 9 one on each square of a 3 by 3 grid so that all the rows and columns add up to a prime number. How many different solutions can you find?

##### Age 7 to 16 Challenge Level:

A Sudoku with clues given as sums of entries.

##### Age 11 to 16 Challenge Level:

The puzzle can be solved with the help of small clue-numbers which
are either placed on the border lines between selected pairs of
neighbouring squares of the grid or placed after slash marks on. . . .

##### Age 7 to 16 Challenge Level:

An ordinary set of dominoes can be laid out as a 7 by 4 magic rectangle in which all the spots in all the columns add to 24, while those in the rows add to 42. Try it! Now try the magic square...