Wk
Strand
Assignment
What the week is
01
Logic & Proof
The Thing That Never Changes
Find what a move cannot touch, and you can rule out the future.
02
Number Structure
Odd, Even and Impossible
Odd and even is not a label. It is a tool that rules things out.
03
Number Structure
Factor Rectangles
Every rectangle you can build from a number is a fact about that number.
04
Number Structure
Primes and Composites
Cross out every number that is a multiple of something. Look at what survives.
05
Number Structure
Building From Primes
Break a number apart however you like. The bottom of the tree is always the same.
06
Number Structure
Multiples That Meet
Two rhythms started together. When do they line up again?
07
Number Structure
The Biggest Shared Factor
The other end of last week. Not where they meet, but what they share.
08
Logic & Proof
Coloring Proves It
Color the board first. The coloring does the arguing.
09
Logic & Proof
The Domino Problem
Sixty-two squares, thirty-one dominoes, and it cannot be done.
10
Dots & Lines
Degree Tells You
Add up every degree in any drawing at all. The answer is never odd.
11
Dots & Lines
Trace It or Prove You Cannot
The old bridge puzzle, settled in one line, without walking anywhere.
12
Logic & Proof
Impossible Fair
Six claims. Prove each one, or knock it down. You may not shrug.
13
Logic & Proof
Case Files
Everything from the first twelve weeks, in one folder.
14
Number Structure
Divisible by 2, 5 and 10
Why does only the last digit matter? There is a reason, and it is short.
15
Number Structure
Divisible by 3 and 9
Add the digits. It is not a trick, and here is why it works.
16
Number Structure
Casting Out Nines
A real check on multiplication, from the rule you proved last week.
17
Number Structure
Wrapping Around, Again
Casting out nines was not a trick. It was arithmetic on a wheel.
18
Number Structure
The Day of the Week
A whole year on a seven-wheel, and no counting on fingers.
19
Shape & Space
Lines of Symmetry
Fold it. If the two halves land on each other, you found a line.
20
Shape & Space
Turning a Shape
Fold lines are not the only kind of symmetry. Some shapes only turn.
21
Shape & Space
The Eight Ways to Move a Square
Every move that leaves a square looking the same. There are exactly eight.
22
Shape & Space
Angles That Must Add Up
Tear the three corners off any triangle at all. They make a straight line.
23
Shape & Space
Tiling the Floor
Only three regular shapes tile a floor. The reason is one division.
24
Shape & Space
Impossible Tilings
Two boards, one corner different, and the answers are not the same.
25
Logic & Proof
Puzzle Fair
A little of everything from Weeks 14 to 24.
26
Ways of Counting
Choosing a Team
Line them up, then divide out the orderings you did not want.
27
Ways of Counting
The Triangle Grows
Every number is the two above it added together, and that rule builds the whole thing.
28
Ways of Counting
The Triangle and the Teams
Last week's triangle and the week before's teams are the same numbers.
29
Dots & Lines
Trees
Joined up, with no way round. Count the lines and you will find a rule.
30
Dots & Lines
The Cheapest Network
Join every town for the least money. The answer is always a tree.
31
Steps & Rules
Two Ways to Multiply
Two methods, the same answer, and a fair way to compare the work.
32
Steps & Rules
The Euclid Machine
Take the smaller from the bigger, over and over. It always stops, and where it stops matters.
33
Fractions
The Same Point on the Line
Equivalent fractions are not two things that are equal. They are one point with two names.
34
Fractions
Parts of a Hundred
A hundred squares, and two ways to say the same shading.
35
Logic & Proof
The Weighing Puzzles
How much can one weighing possibly tell you? Count before you weigh.
36
Logic & Proof
The Proof File, Finished
Thirty-three pages of reasons. This week they become one folder.