What is the latest version of the Apple iOS operating

Given below an equation having four blanks you have to check from the alternatives which among the given is correct?

21 _ 51 _ 7 _ 12 _ 75

After interchanging the given two signs, what will be the value of the given equation?

X and –

64 + 15 ÷ 90 - 120 X 17

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

If the ‘-’ and ‘×’ are interchanged, What will be the value of the following equation?

34 × 22 + 192 ÷ 12 – 8

Which among the given operators should replace the “%” (in the same order) in the given expression below:

5 % 10 % 5 % 36 % 15 % 6

What will be the value of expression if the numbers/digits ‘(30)’ and ‘(13)’ are interchanged?

78 ÷ 30 × 6 + 13 - 14 + 12

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

3 * 12 * 4 * 5 * 4 * 116

Which two signs need to be interchanged to make the following equation correct?

75 – 18 × 80 ÷ 16 + 40 = 125

Select the correct combination of the mathematical signs to replace the ‘@’ symbols in the below equation and thereby balance it: