Question

What should be added to \[3.189\] to get \[7\]?

Answer 1

Hint: Here we are asked to find a number so that we get \[7\] on adding \[3.189\] to it. We will first assume a variable for a required number. Then by using that variable we will convert the given statement into an equation. On solving that equation, we get the value of the variable we assumed, that is, the required number.

Complete step-by-step solution:
We aim to find a number, which should give the result as seven on adding it to a number \[3.189\].
We will solve this problem by converting the given statement to an equation.
Let us assume that the required number is \[x\] that is the number to be added to a decimal number \[3.189\] to get seven.
Now let us form an equation from a given statement. It is given that a number to be added to a decimal number \[3.189\] so that we get the answer as seven. This statement can be written as an equation
\[3.189 + x = 7\]
Let us solve this equation to find the value of the unknown variable \[x\].
Consider the equation \[3.189 + x = 7\]
We need to find the value of the unknown variable \[x\] so keeping that alone on one side and transferring other terms to the other side we get
\[x = 7 - 3.189\]
Now we got the unknown variable alone on one side. Now let us simplifying the terms on the right-hand side, we get
\[x = 3.811\]
Thus, we got the value of the unknown variable \[x\] which is the required number.
Let us check whether the value of the unknown variable \[x\] that we found is correct or not. This can be done by substituting the value of the unknown variable \[x\] in the equation that we formed.
\[3.189 + x = 7 \Rightarrow 3.189 + 3.811 = 7\]
\[ \Rightarrow 7.000 = 7\]
Thus, we verified that the value we found is correct.

Note: Solving a simple equation can be done by three methods: Trial and error method, Systematic method, and Transposition method. Here we have used the transposition method that is keeping the unknown variable alone on one side of the equation and transferring the remaining all terms to another side. This method is simple and quick when compared to the other two methods.