We are asked to translate the following phrase or sentence into a math expression or equation.
"One less than four times a number yields 127"
Let m be the unknown number.
Mathematically, we can write
One less than four times a number means 4m - 1, yields 127 means it is equal to 127.
Since there is an equal sign it is called an equation.
Therefore, the mathematical equation for the given word problem is