The operation on \(x\) is “+ 21”.

Reverse this by subtracting 21 from both sides:

\(x + 21 = 40 \Rightarrow x = 40 - 21 = 19\).

Answer: 19

Think of the expression as \(60 - c\).

Move the 60 first by subtracting 60 from both sides:

\(60 - c = 35 \Rightarrow -c = 35 - 60 = -25\).

Now reverse the “negative” by multiplying by \(-1\):

\(c = 25\).

Answer: 25

The operation on \(a\) is “− 21”.

Reverse this by adding 21 to both sides:

\(a - 21 = 40 \Rightarrow a = 40 + 21 = 61\).

Answer: 61

Here \(x\) is being divided by 32.

Reverse this by multiplying both sides by 32:

\(x = 160 \times 32 = 5120\).

Answer: 5120

Here \(x\) is being multiplied by 24.

Reverse this by dividing both sides by 24:

\(x = 72 \div 24 = 3\).

Answer: 3