| Easy | Medium | Hard | Extreme |
ADD 4 matchsticks to make the equation true.
The following rules apply:
- No number is greater than 9
- Negative numbers are not allowed
- You may not change the equal (=) sign
23 September 2022
662. Mathematical: 5 minus 3 is not 4
ADD 4 matchsticks to make the equation true.
The following rules apply:
- No number is greater than 9
- Negative numbers are not allowed
- You may not change the equal (=) sign
10 October 2021
661. Reduce from 4 to 3 square matchsticks
| Easy | Medium | Hard | Extreme |
The size of the layout shown above is exactly 4 square matchsticks. Make sure to understand that A + B is exactly 1 square matchstick.
MOVE 4 matchsticks to reduce the size of the shape to exactly 3 square matchsticks.
25 September 2021
660. Six to five equal triangles
| Easy | Medium | Hard | Extreme |
There are 6 equal triangles in the layout above. MOVE 2 matchsticks to form 5 equal triangles.
07 September 2021
659. Triangle 3X3: Remove 6 leaving 0 triangles
| Easy | Medium | Hard | Extreme |
TAKE AWAY 6 matchsticks so that there are no triangles left.
28 August 2021
658. Mathematical: 0 minus 3 is not 7
| Easy | Medium | Hard | Extreme |
ADD 3 matchsticks to make the equation true.
The following rules apply:
- No number is greater than 9
- Negative numbers are not allowed
- You may not change the equal (=) sign
03 August 2021
657. Change the 2:3:4 ratio to 2:2:5
| Easy | Medium | Hard | Extreme |
The above square is divided into 3 parts in the ratio 2:3:4. Change this ratio to 2:2:5 by moving only 1 matchstick.
29 July 2021
656. Three right angles
| Easy | Medium | Hard | Extreme |
Three matchsticks form 2 right angles as shown in Figure A above. By moving only 1 matchstick you can create 3 right angles as shown in Figure B. However, this is only one solution and there are 7 more where 3 right angles can be created. Can you find them all?
The rules are:
- Start each time with the layout as in Figure A.
- Move only 1 matchstick.
- You may not move the horizontal matchstick in Figure A.
27 July 2021
655. Four to six squares
| Easy | Medium | Hard | Extreme |
Move only 2 matchsticks to create 6 squares. The squares are allowed to differ in size.
However, squares must be linked and each matchstick must form the side of at least one square.
10 July 2021
654. Increase the inner triangles
06 July 2021
653. The farmer and his 4 sons
| Easy | Medium | Hard | Extreme |
A farmer lives on the area marked "A" on his farm. He decides to divide the rest of the farm between his 4 sons with the SIZE and SHAPE of each of the 4 farms exactly the same.
Add as many matchsticks as you want to the layout to show how he has done this.
04 July 2021
652. Three square units extreme
| Easy | Medium | Hard | Extreme |
Credit: The Moscow puzzles (1972) Boris A. Kordemsky
The length of a matchstick is 1 unit, so in the layout above 12 matchsticks were used to create an area "W" of 3 square units. (see puzzle 121 and also how area W was calculated below)
There is another way to create 3 square units, but you may NOT MOVE the matchsticks which from line AC. Can you find it?
Take note of the calculations below as you might need some of the information in your solution.
The area W was calculated as:
= Total area ABC - area X - area Y - area Z
= 1/2(3 X 4) - 1 - 1 - 1
= 3 square units
Angle 𝛳 was calculated as:
= arcsine(AB/AC)
= arcsine(3/5)
= 36.869898 degrees
We must now proof that the area of the parallelogram is 3 square units.
To calculate the height:
sin𝛳 = height/1
height = sin(36.869898)
height = 0.6 unit
The area of the parallelogram is:
= base X height
= 5 X 0.6
= 3 square units
To calculate the height:
sin𝛳 = height/1
height = sin(36.869898)
height = 0.6 unit
The area of the parallelogram is:
= base X height
= 5 X 0.6
= 3 square units
03 July 2021
651. Three square units
| Easy | Medium | Hard | Extreme |
The length of a matchstick is 1 unit. Use 12 matchsticks to create an area of 3 square units. To make your life easier, 8 of the 12 matches have already been placed in the correct positions.
19 June 2021
650. Three squares different in size
| Easy | Medium | Hard | Extreme |
There are 5 squares in the layout above, 4 small and 1 big.
Move 2 matchsticks to create 3 squares of 3 different sizes.
16 June 2021
649. Three-way bridge
| Easy | Medium | Hard | Extreme |
There are three islands in the ocean and your challenge is to construct a bridge to connect them. Unfortunately, as can be seen with matchsticks A, B and C, the length of a matchstick is just too short to connect the islands directly.
How would you construct an interlocking bridge, that can actually carry some weight in real life, by only using matchsticks A, B and C? Also, the three matchsticks are not allowed to touch the ocean.
08 June 2021
648. Divide into 2 parts
| Easy | Medium | Hard | Extreme |
MOVE 2 matchsticks in the layout above to divide it into 2 parts equal in shape and size.
04 June 2021
647. Rugby
| Easy | Medium | Hard | Extreme |
A rugby player missed a kick to goal by kicking the ball to the right of the posts and also lower than the crossbar.
MOVE only 2 matchsticks to make the ball go through the posts and over the crossbar. You may not move the ball.
03 June 2021
646. Cross to squares
| Easy | Medium | Hard | Extreme |
There are no squares in the layout above. Move 4 matchsticks to change the cross into 4 EQUAL squares.
02 June 2021
645. Fix the equation
| Easy | Medium | Hard | Extreme |
You would need math skills to solve this one.
The equation 7/9 = 3 is not true. Move only 2 matchsticks to make it true.
01 June 2021
644. Polygon with 7 sides
| Easy | Medium | Hard | Extreme |
Shown above is an eight sided convex polygon built from 2 squares and 6 triangles. 17 matchsticks were used to achieve this. The outside angles are all greater than 180 degrees as illustrated with angle "a" above.
Create your own convex polygon. The following rules apply:
1. Polygon must have 7 sides
2. 12 matchsticks to be used
3. All outside angles to be greater than 180 degrees
4. There must be 3 equal sized triangles
5. There must be 2 equal sized squares
6. All matchsticks must be flat on the surface.
30 May 2021
643. Cup and saucer
| Easy | Medium | Hard | Extreme |
Move 4 matchsticks to convert the cup and saucer into 3 DIFFERENT in size triangles.
29 May 2021
642. Stacked triangles
| Easy | Medium | Hard | Extreme |
In the figure above are 4 equal triangles. Move 4 matchsticks to create 2 equal triangles.
28 May 2021
641. Three different squares
| Easy | Medium | Hard | Extreme |
MOVE 3 matchsticks to create only 3 squares. The 3 squares must have 3 DIFFERENT sizes.
Note that all matchsticks form part of a square i.e. there are no redundant matchsticks. There are also other solutions.
24 May 2021
640. Big and small squares
| Easy | Medium | Hard | Extreme |
There are 4 squares in the layout above. A broken matchstick is exactly half the length of a full length matchstick. Also, matchstick A is placed exactly in the middle of matchstick B.
Move 3 matchsticks to create 8 squares. All matchsticks don't have to be flat on the surface and square sizes may differ.
22 May 2021
639. From three to two squares
| Easy | Medium | Hard | Extreme |
Reduce the number of squares from 3 to 2 by moving 3 matchsticks. Squares may differ in size.
21 May 2021
638. Create 5 triangles
| Easy | Medium | Hard | Extreme |
Move 4 matchsticks to create 5 triangles. The triangles may differ in size.
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