Young Saul, a budding mctaemhtiaian and printer, is making himself a fake ID. He needs it to say he’s 21. The problem is he’s not using a computer, but rather he has some symbols he’s bought from the store, and that’s it. He has one 1, one 5, one 6, one 7, and an unlimited supply of + – * / (the operations addition, subtraction, multiplication and division). Using each number exactly once (but you can use any number of +, any number of -, …) how can he get 21 from 1, 5, 6, 7?Note: you can’t do things like 15+6 = 21. You have to use the four operations as ‘binary’ operations: ((1+5)*6)+7.
No hablo mctaemhtiaian
To help young Saul create a mathematical expression that results in 21 using the given numbers and operations, we can explore various combinations. Let's break it down step by step:
Step 1: Identify the target number
Young Saul wants to make a fake ID that says he's 21. So, the target number is 21.
Step 2: Understand the available numbers
Young Saul has the numbers 1, 5, 6, and 7. He can use each number once, but can use the operations (+, -, *, /) multiple times.
Step 3: Generate possible expressions
Let's try different combinations of expressions to achieve the target number 21. Remember to use the operations as binary operations, meaning they take two inputs.
Expression 1: ((1 + 5) * 6) + 7
Explanation: Young Saul first adds 1 and 5, which gives 6. Then, he multiplies 6 by 6, resulting in 36. Finally, he adds 36 and 7, which gives 43.
This expression doesn't result in the target number (21).
Expression 2: (1 + 5) * (6 - 7)
Explanation: Young Saul adds 1 and 5, which gives 6. Then, he subtracts 7 from 6, resulting in -1.
This expression also doesn't match the target number.
Expression 3: (1 * 5) + (6 * 7)
Explanation: Young Saul multiplies 1 by 5, which gives 5. Then, he multiplies 6 by 7, resulting in 42. Finally, he adds 5 and 42, which gives 47.
Again, this expression doesn't yield the target number.
As we can see, none of the expressions tried so far result in 21. Young Saul needs to find other combinations.
Expression 4: (1 * 5) - (7 - 6)
Explanation: Young Saul multiplies 1 by 5, which gives 5. Then, he subtracts 7 from 6, resulting in -1. Finally, he subtracts -1 from 5, giving 6.
This expression also doesn't match the target number.
Expression 5: (7 - 5) * (6 - 1)
Explanation: Young Saul subtracts 5 from 7, which gives 2. Then, he subtracts 1 from 6, resulting in 5. Finally, he multiplies 2 by 5, giving 10.
This expression doesn't match the required target number.
After exploring various combinations, we haven't found an expression that results in the target number of 21 using the given numbers and operations. It seems that we cannot create a valid fake ID for young Saul based on the given constraints.