German math problem 3 5 7 is equal to 1 1 to 20. The method is as follows:

The result is 1 1:

3? +7-5?

= 9+7-5?

= 1 1

The result is 12:

3! ×(7 -5)

=3×2× 1×(7 -5)

=3×2× 1×2

= 12

The result is 13:

[√(-3+7)]? + 5

= [√4)]? + 5

=2? +5

=8+5

= 13

The result is 14:

3! +7+5?

=3×2× 1+7+ 1

=6+7+ 1

= 14

The result is 15:

3+7+5

= 15

The result is 16:

3×7-5?

=2 1-5

= 16

The result is 17:

-3? -7+5?

=- 1-7+25

= 17

The result is 18:

3! +7+5?

=3×2× 1+7+5

=6+7+5

= 18

The result is 19:

(-3+7)! -5?

=4×3×2× 1-5

=24-5

= 19

The result is 20:

(-3+7)×5?

=4×5

=20