Sunday Afternoon Maths VL

 Posted on 2015-08-02 

Integer part

Let \(\lfloor x\rfloor \) denote the integer part of \(x\) (eg. \(\lfloor 7.8\rfloor =7\)).
When are the following true:
a) \(\lfloor x+1\rfloor = \lfloor x\rfloor + 1\)
b) \(\lfloor nx\rfloor = n\lfloor x\rfloor\) (where \(n\) is an integer)
c) \(\lfloor x+y\rfloor = \lfloor x\rfloor +\lfloor y\rfloor \)
d) \(\lfloor xy\rfloor = \lfloor x\rfloor \lfloor y\rfloor \)

Show answer & extension

Make the sums

Put the digits 1 to 9 (using each digit exactly once) in the boxes so that the sums reading across and down are correct. The sums should be read left to right and top to bottom ignoring the usual order of operations. For example, \(4+3\times2\) is 14, not 10.
+-= 4
+ - ×
-×= 27
- × ÷
×÷= 16

Show answer & extension

Tags: numbers, grids
If you enjoyed these puzzles, check out Advent calendar 2019,
puzzles about taxicab geometry, or a random puzzle.


Show me a random puzzle
 Most recent collections 

Advent calendar 2019

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018

Sunday Afternoon Maths LXVI

Cryptic crossnumber #2

List of all puzzles


ave averages balancing bases people maths differentiation routes planes time complex numbers cube numbers trigonometry probability cards fractions square roots sum to infinity dates rugby rectangles algebra grids arrows money elections crosswords floors number volume factorials 2d shapes cryptic crossnumbers numbers parabolas coordinates books integers digital clocks palindromes crossnumbers triangles advent pascal's triangle taxicab geometry factors the only crossnumber remainders addition division wordplay square numbers speed scales area polygons ellipses christmas prime numbers crossnumber surds calculus proportion sport sequences squares odd numbers dice median dominos logic regular shapes chalkdust crossnumber geometry spheres gerrymandering integration shapes percentages dodecagons chess clocks 3d shapes mean angles triangle numbers products doubling coins perfect numbers indices graphs lines functions circles probabilty cryptic clues colouring folding tube maps star numbers tiling multiplication symmetry multiples shape games means perimeter irreducible numbers range sums hexagons chocolate unit fractions partitions menace quadratics digits


Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2020