## 18 May 2018

### 587. Mathematical: 0 minus 5 is not 1

 Easy Medium Hard Extreme

MOVE only 1 matchstick to make the statement true.

## 12 May 2018

### 586. Little square and rectangle

 Easy Medium Hard Extreme

Four matchsticks form a little square as shown above. Your challenge is to create a rectangle with size EXACTLY 3 times the size of the little square.

Note the following:
1. All matchstick heads have been removed.
2. The 4 matchsticks are exactly the same. (thickness, length etc)
3. Only the 4 matchsticks above may be used in your solution.
4. Not all matchsticks have to be used in your solution.
5. You are allowed to break one matchstick.

## 05 May 2018

### 585. Four-sided figures

 Easy Medium Hard Extreme

A four-sided figure (square or rectangle) can be stand-alone or combined. How many four-sided figures do you count with at least one broken matchstick in them?

There are 14 four-sided figures in total

Stand-alone: C, D, G
Two combined: B+C, D+E, D+F, F+G, G+H
Three combined: A+B+C, F+G+H, E+G+H
Five combined: A+B+C+D+E, D+E+F+G+H
Eight combined: A+B+C+D+E+F+G+H

## 29 April 2018

### 584. The four rectangles

 Easy Medium Hard Extreme

There are 3 rectangles of size 2X1 in the layout above. They are ABDC, EGLJ and FHMK.

Move 3 matchsticks to create FOUR equal rectangles each of size 2X1.

The four 2X1 rectangles are ABDC, FHMK, CDON and GPQL

## 21 April 2018

### 583. Divide the square

 Easy Medium Hard Extreme

Divide the square into 3 parts by adding 8 matchsticks. The 3 parts must be equal in size but not necessarily in shape.

## 14 April 2018

### 582. Mathematical: 4 plus 5 is not 5

 Easy Medium Hard Extreme

MOVE 3 matchsticks to make the equation true. Consider yourself brilliant if you can find the 3 solutions.

## 07 April 2018

### 581. Remove 6 leaving 3 squares

 Easy Medium Hard Extreme

Take away 6 matchsticks to leave you with 3 equal squares. The 3 squares may not touch.

## 30 March 2018

### 580. Divide the rectangle in ratio 3:4:5

 Easy Medium Hard Extreme

Divide the rectangle into 3 areas with ratio 3:4:5 by placing 7 matchsticks inside the layout.

There are also other solutions.

## 25 March 2018

### 579. Mathematical: 6 plus 0 is not 7

 Easy Medium Hard Extreme

TAKE AWAY 4 matchsticks to make the equation true.

## 17 March 2018

### 578. Remove 3 leaving 3 triangles

 Easy Medium Hard Extreme

TAKE AWAY 3 matchsticks to leave you with 3 equal triangles.

## 03 March 2018

### 577. One square

 Easy Medium Hard Extreme

Place the 8 matchsticks in such a way that it forms a square. The 4 broken matchsticks have the same length but are not half the length of the full matchstick.

## 17 February 2018

### 576. Divide into 4 areas

 Easy Medium Hard Extreme

Add 15 matchsticks inside the layout above to create 4 areas equal in SIZE.

## 11 February 2018

### 575. Three matchstick node notations

 Easy Medium Hard Extreme

Figures A and B above are two examples illustrating how "nodes" and "node notations" are formed by using 3 matchsticks. There are 7 more "node notations" using only 3 matchsticks. Can you find them all?

The rules are:
1. Matchstick heads can be ignored
2. All matchsticks must be flat on the surface
3. Each matchstick must touch at least one other matchstick

## 04 February 2018

### 574. Triangle 3X3: Remove 4 leaving 6 triangles

 Easy Medium Hard Extreme

Take away 4 matchsticks to leave only 6 triangles. The triangles must be equal in size.

There are also other solutions.

## 28 January 2018

### 573. The third grader puzzle

 Easy Medium Hard Extreme

This puzzle was given to third graders in a school somewhere in the world...

ADD only 1 matchstick to make the equation true.

## 13 January 2018

### 572. Mathematical: 4 minus 7 is not 8

 Easy Medium Hard Extreme

TAKE AWAY 3 matchsticks to make the equation true.

## 23 December 2017

### 571. Change the 2:3:4 ratio to 1:1:1

 Easy Medium Hard Extreme

The above square is divided into 3 parts in the ratio 2:3:4. The ratio must be changed to 1:1:1 by moving only 1 matchstick.

The ratio 3:3:3 is equal to 1:1:1.

## 16 December 2017

### 570. The biggest number

 Easy Medium Hard Extreme

ADD 3 matchsticks to form the BIGGEST possible number. Your solution should only have THREE digits.

## 09 December 2017

### 569. Divide into 4 areas

 Easy Medium Hard Extreme

Add 10 matchsticks inside the layout above to create 4 areas equal in SIZE and SHAPE.

## 02 December 2017

### 568. Change to numerical equation

 Easy Medium Hard Extreme

The above equation is not true. Move 2 matchsticks to change it to a valid numerical equation.

## 25 November 2017

### 567. The wood log problem

 Easy Medium Hard Extreme

In a factory are 5 machines with each machine producing 5 pieces of compressed wood logs. The weight of each wood log is 500 grams.

However, one of the 5 machines is faulty and produces 5 logs with weight slightly more than 500 grams for each log. You do not know which machine is faulty and also not by how much.

Available in the factory is a digital single-tray scale. (not a two-tray balance scale) You are allowed to weigh as many logs as you wish at a time, but may use the scale only twice. How can you find the faulty machine?

STEP 1:
Place one log from each machine on the scale and weigh. Let's assume your answer is 2 510 grams. You now know the faulty machine produces 10 grams more for each log. (2 510 grams - 2 500 grams) But you still don't know which machine is faulty...

STEP 2:
Place the logs on the scale as shown above. The total weight is supposed to be 7 500 grams. (15 logs X 500 grams) Let's assume your answer is 7 530 grams which means there are 30 grams more than expected. (7 530 grams - 7 500 grams) Your faulty machine would therefore be machine 3. (30 grams / 10 grams) If machine 1 was faulty the weight would have been 7 510 grams, machine 2 would be 7 520 grams etc.

## 18 November 2017

### 566. Matchstick Grid: Diagonal heads

 Easy Medium Hard Extreme

This puzzle is similar to but different from number 500.

If you count the matchstick heads in each diagonal, vertical and horizontal row you will get to the numbers as shown above.

Your challenge is to rearrange the matchsticks to have:
- 4 heads in each row
- 4 heads in each column
- 8 heads in each diagonal row.

Your solution must still be a 2X2 matchstick grid.

## 12 November 2017

### 565. Move 2 to form 2 triangles

 Easy Medium Hard Extreme

Easy, but people seem to struggle with this one...

Move 2 matchsticks to form only 2 triangles.

Nobody said the 2 triangles must be equal in size!

## 11 November 2017

### 564. Triangle 3X3: Remove 6

 Easy Medium Hard Extreme

TAKE AWAY 6 matchsticks to leave you with 6 triangles. All triangles must be equal in size.

## 05 November 2017

### 563. Square 3X3: Take away 8

 Easy Medium Hard Extreme

Take away 8 matchsticks to leave only 5 equal squares.