## cathyangs 3 years ago Please help an 8-year-old! (it's not me) Using only the digits 1, 4, 5, and 7, and one addition sign, and one subtraction sign, find a way to get the answer 19. ex: 57-1+4

1. cathyangs

it can only have an addition sign and a subtraction sign, no brackets or anything. No powers, bases or anything like that either.

2. cathyangs

basically something you can do on a non-programming, elementary-school calculator

3. shelovespiano

can you use the digits more than once?

4. cathyangs

nope.

5. shelovespiano

...Well, the closest I can get is 17+5-4=18 :/

6. cathyangs

XD that's how close I got.

7. saifoo.khan

We can use only + and - ?

8. cathyangs

yup, and you can only use each one time.

9. saifoo.khan

THinking..

10. cathyangs

I do so believe that this is the hardest third-grade question on openstudy...OTL

11. UnkleRhaukus

not possible

12. cathyangs

...ok... why? This is a "three-star" problem on a 3rd grader's hw...it's not possible?

13. Tiamat

Does it have to use ALL the digits and signs?

14. cathyangs

yes. the image is a calculator with all the keys you have to use once checked.

15. UnkleRhaukus

can you please check to see if the whole question has be written correctly

16. cathyangs

it is. here is the exact phrasing: Below each calculator, write a number sentence to give the answer shown. The symbols and digits to use are checked on each calculator. the answer is 19. The digits and symbols are 1, 4, 5, 7, -, + and =.

17. Tiamat

Wait, if that's the exact question, then does it say in the -directions- to use everything once? If so, then I have to agree with UnkleRhaukus. I can only get as far as 18 with these numbers.

18. saifoo.khan

lol, same here.. i dont knw where to add 1. keep on gettinh 18.

19. cathyangs

it does't explicitly say, but all the other questions like that on the same sheet only use each digit once.

20. Tiamat

Ahhhh. This is making my brain hurt. Either it's a type of trick question where you do use them more than once, like: 17 + 5 - 4 + 1 = 19 Or a typo. I'm sorry, I just can't figure this one out. ):

21. saifoo.khan

might be a mis-print in the book?

22. cathyangs

it's not a book...but perhaps.