ArchiveShow me a Random Puzzle
Most Recent Collections
Sunday Afternoon Maths LXIXYZ
Sunday Afternoon Maths LXWhere is Evariste?
Bending a Straw
Sunday Afternoon Maths LIXTurning Squares
List of All Puzzles
Tagstime geometry 2d shapes 3d shapes numbers spheres trigonometry complex numbers algebra lines graphs coordinates odd numbers fractions differentiation calculus folding tube maps ellipses triangle numbers money bases triangles squares area square numbers chess probability circles averages speed sport multiples dates factors parabolas functions logic cards games people maths shape prime numbers irreducible numbers probabilty angles proportion dice integration sum to infinity dodecagons hexagons multiplication factorials coins shapes regular shapes colouring grids floors integers rugby crosswords percentages digits sums rectangles clocks menace routes taxicab geometry remainders chalkdust crossnumber palindromes sequences means unit fractions division square roots surds doubling quadratics indices symmetry planes volume number partitions ave pascal's triangle mean advent arrows addition
Today's number is 191 more than one of the other answers and 100 less than another of the answers.
Today's number is the number of three digit numbers that are not three more than a multiple of 7.
Today's number is a palindrome. Today's number is also the number of palindromes between 111 and 11111 (including 111 and 11111).
Today's number is a multiple of three. The average (mean) of all the answers that are multiples of three is a multiple of 193.
Earlier this year, I wrote a blog post about different ways to prove Pythagoras' theorem. Today's puzzle uses Pythagoras' theorem.
Start with a line of length 2. Draw a line of length 17 perpendicular to it. Connect the ends to make a right-angled triangle. The length of the hypotenuse of this triangle will be a non-integer.
Draw a line of length 17 perpendicular to the hypotenuse and make another right-angled triangle. Again the new hypotenuse will have a non-integer length. Repeat this until you get a hypotenuse of integer length. What is the length of this hypotenuse?
The sum of all the numbers in the eighth row of Pascal's triangle.
Clarification: I am starting the counting of rows from 1, not 0. So (1) is the 1st row, (1 1) is the 2nd row, (1 2 1) is the 3rd row, etc.
The smallest number whose sum of digits is 25.