Which scientist discovered

If the following interchanges are made in signs, then what would be the value of the following expression?

48 X 63 + 2 ÷ 9 - 35 

If + means ÷, × means –, – means ×,  ÷ means +, then 32 + 16 – 13 x 18 ÷ 2 = ?

Select the correct combination of mathematical signs that can sequentially replace the * signs and make the equation correct.

45 $ 5 $ 68 $ 17$ 12 = 37

If '÷' means '+', '+' mean '-', 'x' means '÷' and '-' means 'x', then what will be the value of the given expression:

12 – 6 x 2 + 5 ÷ 9

If ‘A’ means (÷), ‘B’ means (×), ‘C’ means (+), and ‘D’ means (-), then what is the value of the expression:

Select the correct combination of mathematical signs that can sequentially replace the “@” sign and balance the following equation.