## 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.

## 29 October 2017

### 562. Mathematical: 5 minus 1 is not 1

 Easy Medium Hard Extreme

ADD 2 matchsticks to the layout above to make the equation true. Can you find both solutions?

## 28 October 2017

### 561. Pathway with 7 matchsticks revisited

 Easy Medium Hard Extreme

This puzzle is similar to but different from Number 492.

7 matchsticks are used to form a pathway as shown above. The challenge is to start at a point, move in the direction of the matchstick heads and visit each of the 7 matchsticks only once.

A solution is not possible in the existing figure above, but by changing the direction of only 2 matchsticks it can be achieved. How would you do this?

Change the directions of matchsticks 1 and 5. The pathway is then from matchstick 1 to 7.

## 22 October 2017

### 560. Find the next number

 Easy Medium Hard Extreme

Think out of the box to solve this one!

The number of letters in the different words of the question represent the numbers.

FIND = 4
THE = 3
NEXT = 4
NUMBER = 6

## 21 October 2017

### 559. Divide into 4 areas

 Easy Medium Hard Extreme

Add 11 matchsticks inside the layout above to create 4 areas equal in size.

## 15 October 2017

### 558. Move 1 and still have 5 squares

 Easy Medium Hard Extreme

There are 5 equal squares in the figure above. Move 1 matchstick so you still have 5 equal squares.

## 14 October 2017

### 557. Turn the direction

 Easy Medium Hard Extreme

Your challenge is to turn the 4 matchsticks around so they are all facing the other way. The rules are:

1. Turn any 3 matchsticks in each move
2. You have 4 moves to achieve this.

## 08 October 2017

### 556. Letters and Numbers

 Easy Medium Hard Extreme

Replace the letters with numbers to make the addition true. To help you to get going it can be revealed that L=8, A=9 and C=5.

2 1 2 4
+ 9 3 7 8
----------
1 1 5 0 2

(By just looking at the leftmost letters it should be clear that F can only be 1)

## 07 October 2017

### 555. Change the 3:4:5 ratio to 1:3:8

 Easy Medium Hard Extreme

Place 6 matchsticks inside a 4X3 rectangle as shown above. The rectangle is divided into 3 parts in the ratio 3:4:5

Move only 1 matchstick inside the rectangle to change the ratio to 1:3:8

## 01 October 2017

### 554. Count the 4-sided figures

 Easy Medium Hard Extreme

Ho many four-sided figures (squares and rectangles) do you count in the layout above?

There are 14 in total:

1. ABDF
2. ABCG
3. ICDE
4. GIEF
5. GCDF
6. HJKL
7. MNOP
8. QRST
9. HJZY
10. YZKL
11. UNVL
12. QXKW
13. YI2L
14. IZK2

## 30 September 2017

### 553. Mathematical: 5 minus 9 is not 7

 Easy Medium Hard Extreme

TAKE AWAY 3 matchsticks to make the above equation true.

## 24 September 2017

### 552. Change the ratios

 Easy Medium Hard Extreme

Place 6 matchsticks inside a 3X3 square as shown above. The square is divided into 3 parts in the ratio 2:3:4

Move only 1 matchstick inside the square to change the ratio to 1:3:5

## 23 September 2017

### 551. Route map: 1- and 2-way roads

 Easy Medium Hard Extreme

Shown in the puzzle above are one- and two-way roads. In total, how many different routes are there from point A to point J? You may only move in the direction of the matchstick heads and only travel on the same road once during the route.

There are 12 routes in total:

1. ABCFJ
2. ABEFJ
3. ABEHJ
10. ABEDGHJ
11. ABCFEDGHJ
12. ABCFEHJ

## 17 September 2017

### 550. Move 3 to form 4 squares

 Easy Medium Hard Extreme

There are 5 equal squares in the layout above. Move 3 matchsticks to have only 4 squares equal in size.

## 16 September 2017

### 549. Divide the square into 2 parts

 Easy Medium Hard Extreme

5 matchsticks, placed horizontally and vertically, divide the square into 2 equal parts as shown above. The 2 parts are equal in shape and size. Another obvious solution would be 1 vertical and 4 horizontal matchsticks based on the same principle.

But there is another clever solution! In what other way can you place the 5 matchsticks inside the square to divide it exactly into 2 parts equal in shape and size?

AC is exactly the length of 3 matchsticks and BC exactly 4 matchsticks. Applying the Pythagoras's theorem you can proof that AB is exactly the length of 5 matchsticks:
(AB)² = (BC)² + (AC)²
(AB)² = 16 + 9
AB = √25
AB = 5

## 10 September 2017

### 548. Mathematical: 9 minus 0 is not 1

 Easy Medium Hard Extreme

ADD 1 matchstick to make the equation true.

## 09 September 2017

### 547. Pathway with 14 matchsticks

 Easy Medium Hard Extreme

This puzzle is similar to numbers 492 and 502.

14 matchsticks are used to form a pathway as shown above. The challenge is to start at a point, move in the direction of the matchstick heads and visit each of the 7 matchsticks only once.

A solution is not possible in the existing figure above, but by changing the direction of only 1 matchstick it can be achieved. Which matchstick would you change and can you find the pathway?

The direction of matchstick 3 is changed.

One pathway is to start with matchstick 1 and end with matchstick 14.

## 03 September 2017

### 546. Change to two

 Easy Medium Hard Extreme

Somebody writes the above on a piece of paper. The answer is obviously 1, but what action can you perform to make the answer 2?

Turn the page upside down then 8-6 equals 2.

## 02 September 2017

### 545. Divide into two identical pieces

 Easy Medium Hard Extreme

Add 10 matchsticks to the square above to divide it into 2 pieces. The 2 pieces must be equal in size and shape.

There are also other variations of this solution.