- #1

- 508

- 0

OK, you have the numbers

1 2 3 4 5 6 7 8 9 0.

You may insert some + signs and one = sign so to make a valid equation.

Like

12+34+5+6+78=90 (oops, false! )

Happy posting, and a big thanks to Greg who does a great job IMO.

- Thread starter arcnets
- Start date

- #1

- 508

- 0

OK, you have the numbers

1 2 3 4 5 6 7 8 9 0.

You may insert some + signs and one = sign so to make a valid equation.

Like

12+34+5+6+78=90 (oops, false! )

Happy posting, and a big thanks to Greg who does a great job IMO.

- #2

- 54

- 1

Easy ..

1+2+3+4+5+67+8=90

1+2+3+4+5+67+8=90

- #3

- 508

- 0

Yes. There's more solutions.

- #4

drag

Science Advisor

- 1,062

- 0

1 + 2 + 3 + 4 + 56 + 7 + 8 + 9 = 90

12 + 3 + 45 + 6 + 7 + 8 + 9 = 90

12 + 3 + 45 + 6 + 7 + 8 + 9 = 90

- #5

Njorl

Science Advisor

- 258

- 10

You used the 9's twice drag.

12+3+4+56+7+8=90

1+23+45+6+7+8=90

nothing =890

nothing=7890

etc.

Njorl

12+3+4+56+7+8=90

1+23+45+6+7+8=90

nothing =890

nothing=7890

etc.

Njorl

- #6

Njorl

Science Advisor

- 258

- 10

If 2^{n}-1 is prime, what can you say about (2^{n}-1)*(2^{n-1})?

Njorl

Njorl

- #7

Ben-CS

Perfect!

- #8

Njorl

Science Advisor

- 258

- 10

Absolutely. I thought that would take longer.

Njorl

Njorl

- #9

climbhi

What do you mean perfect?Originally posted by Ben-CS

Perfect!

- #10

Njorl

Science Advisor

- 258

- 10

Factors of 6 are 1,2,3 1+2+3=6

Factors of 28 are 1,2,4,7,14 1+2+4+7+14=28

6 and 28 are perfect.

Njorl

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