-1
$\begingroup$

Start with the numbers 1,2,3,4,5,6,7,8,9,10 in that order and use the four common operations (+ − × ÷) and number concatenation (ie, you may write 123 concatenating 1, 2, 3) to obtain 2020.

Some clarifications:

  • All the ten numbers must be used, in that order, without repetitions.
  • Unary - is allowed; inserting decimal point is also allowed.
  • Number 10 cannot be split as 1 0; it can of course be concatenated with 9 to obtain 910.
  • Concatenation may only be applied to literal digits.
  • Exponentiation is not allowed, even though it is written without any explicit operators.
Improve this question
$\endgroup$
4
  • 4
    $\begingroup$ There seem to be many many solutions to this question. It might be worth considering some tighter restrictions. $\endgroup$
    – hexomino
    Commented Dec 19, 2019 at 9:50
  • $\begingroup$ In particular you should disallow concatenation $\endgroup$
    – Adam
    Commented Dec 19, 2019 at 10:58
  • $\begingroup$ I am not sure that there is a solution without concatenation. $\endgroup$
    – mau
    Commented Dec 19, 2019 at 14:42
  • $\begingroup$ Can we use parentheses ? $\endgroup$
    – Adam
    Commented Dec 19, 2019 at 22:03

4 Answers 4

Reset to default
5
$\begingroup$

Here's one way to do it if we disallow concatenation, division, unary and decimals

$(((1-(2\times 3)+4+(5\times 6)) \times 7) +8 - 9) \times 10 = 2020$

although there will be many others.

Improve this answer
$\endgroup$
2
$\begingroup$

My two cents

(12*34)*5+6*7-8*9+10 = 2020

Improve this answer
$\endgroup$
2
  • 1
    $\begingroup$ Those brackets are not needed. :) $\endgroup$
    – sudhackar
    Commented Dec 19, 2019 at 10:15
  • $\begingroup$ @sudhackar indeed, but it just helps me visually $\endgroup$
    – rhsquared
    Commented Dec 19, 2019 at 10:17
2
$\begingroup$

Here's some

12*34*5-6-7-8-9+10
123+45*6*7+8+9-10
12+34*5*6+78+910
1*2*34*5*6+7-8-9-10
1*23*45+67+8+910

Improve this answer
$\endgroup$
0
$\begingroup$

$((1+2) \div 3+45+67+89) \times 10 = 2020$

Improve this answer
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.