mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

5 December

I make a book by taking 111 sheets of paper, folding them all in half, then stapling them all together through the fold. I then number the pages from 1 to 444.
Today's number is the sum of the two page numbers on the centre spread of my book.
Tags: numbers, books

4 December

Today's number is the number of 0s that 611! (611×610×...×2×1) ends in.

Show answer

3 December

Put the digits 1 to 9 (using each digit exactly once) in the boxes so that the sums are correct. The sums should be read left to right and top to bottom ignoring the usual order of operations. For example, 4+3×2 is 14, not 10. Today's number is the product of the numbers in the red boxes.
++= 11
- + ×
+-= 11
- - -
++= 11
=
-11
=
11
=
11

Show answer

Tags: numbers, grids

1 December

There are 5 ways to write 4 as the sum of 1s and 2s:
Today's number is the number of ways you can write 12 as the sum of 1s and 2s.

Show answer

Tags: numbers

Square and cube endings

Source: UKMT 2011 Senior Kangaroo
How many positive two-digit numbers are there whose square and cube both end in the same digit?

Show answer & extension

Digitless factor

Ted thinks of a three-digit number. He removes one of its digits to make a two-digit number.
Ted notices that his three-digit number is exactly 37 times his two-digit number. What was Ted's three-digit number?

Show answer & extension

Backwards fours

If A, B, C, D and E are all unique digits, what values would work with the following equation?
$$ABCCDE\times 4 = EDCCBA$$

Show answer

Cube multiples

Six different (strictly) positive integers are written on the faces of a cube. The sum of the numbers on any two adjacent faces is a multiple of 6.
What is the smallest possible sum of the six numbers?

Show answer & extension

Archive

Show me a random puzzle
 Most recent collections 

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018

Sunday Afternoon Maths LXVI

Cryptic crossnumber #2

Sunday Afternoon Maths LXV

Cryptic crossnumber #1
Breaking Chocolate
Square and cube endings

List of all puzzles

Tags

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

Archive

Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2019