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

Multiply both sides by \(y\):

\(80 = 20y\).

Now reverse “× 20” by dividing both sides by 20:

\(y = 80 \div 20 = 4\).

Answer: 4

Multiply both sides by \(y\):

\(125 = 5y\).

Reverse “× 5” by dividing both sides by 5:

\(y = 125 \div 5 = 25\).

Answer: 25

Reverse “+ 31” by subtracting 31 from both sides:

\(a = 50 - 31 = 19\).

Answer: 19

Rewrite as \(70 - y = 42\).

Subtract 70 from both sides:

\(-y = 42 - 70 = -28\).

Now reverse the sign by multiplying by \(-1\):

\(y = 28\).

Answer: 28

The operation on \(c\) is “− 23”.

Reverse this by adding 23 to both sides:

\(c = 61 + 23 = 84\).

Answer: 84

Subtract 38 from both sides:

\(-x = 38 - 38 = 0\).

Reverse the sign by multiplying by \(-1\):

\(x = 0\).

Answer: 0

Here \(y\) is divided by 21.

Reverse this by multiplying both sides by 21:

\(y = 6 \times 21 = 126\).

Answer: 126

Reverse “× 10” by dividing both sides by 10:

\(x = 70 \div 10 = 7\).

Answer: 7

Reverse “× 7” by dividing both sides by 7:

\(x = 84 \div 7 = 12\).

Answer: 12

Reverse “+ 32” by subtracting 32 from both sides:

\(x = 32 - 32 = 0\).

Answer: 0

Subtract 25 from both sides:

\(-a = 25 - 25 = 0\).

Reverse the sign by multiplying by \(-1\):

\(a = 0\).

Answer: 0

Subtracting 0 does not change the number, so:

\(y = 27\).

Answer: 27

Reverse “+ 32” by subtracting 32 from both sides:

\(x = 32 - 32 = 0\).

Answer: 0