QUIZ 4. Four Single Digit Numbers
This is a mobile game called "산수의 달인", where you have to generate math formula using addition(\(+\)), subtraction(\(-\)), multiply(\(\times\)), or division(\(\div\)) with given \(4\) numbers.
Caption
For example, if you make \(9 \times (3 + 2)\), then you can clear \(45\) on this picture.
Now let's approach this game in inversed direction. Can you give \(4\) numbers that can generate \(10, 20, 30, 40, 50, 60, 70, 80, 90\)? There can be duplicated numbers. For example, \(6, 7, 4, 1\) can generate followings;
- \(10 = 6+4\)
- \(20 = 4 \times (6-1)\)
- \(30 = 6 \times (4+1)\)
- \(40 = 6 \times (7-1) + 4\)
- \(60 = 6 \times (7+4-1)\)
- \(70 = 7 \times (6+4)\)
- \(80 = (7+1) \times (6+4)\)
But not \(50, 90\).
Click here to read the answer.