How do you simplify the expression $15 - \dfrac{{35}}{7}.2 + 3.4$?

Hint: We will first of all, multiply $\dfrac{{35}}{7}$ with 2 and 3 with 4, then put them in the equation given to us. Now, we will take the least common multiple of denominators and add the fractions.

Complete step-by-step solution:
We are given that we need to simplify the expression given by $15 - \dfrac{{35}}{7}.2 + 3.4$.
We will break the given expression into smaller parts for initial.
First of all, we will simplify $\dfrac{{35}}{7}$. We can write $\dfrac{{35}}{7}$ as follows:
$ \Rightarrow \dfrac{{35}}{7} = \dfrac{{7 \times 5}}{7}$
Crossing – off 7 from the numerator and denominator on the right hand side of the above mentioned expression, we will then obtain the following expression with us:-
$ \Rightarrow \dfrac{{35}}{7} = 5$
Now, let us multiply 5 with 2, we will have the following expression with us:-
$ \Rightarrow 5.2 = 5 \times 2$
Simplifying the right hand side of above expression by doing the calculations, we will then obtain the following expression with us:-
$ \Rightarrow 5.2 = 10$
Now, we can combine the simplifications done above, we will be able to write the following equation with us:-
$ \Rightarrow \dfrac{{35}}{7}.2 = 10$ ……………(1)
Now, we will multiply 3 with 4, we will then obtain the following expression with us:-
$ \Rightarrow 3.4 = 3 \times 4$
Simplifying the right hand side of above expression by doing the calculations, we will then obtain the following expression with us:-
$ \Rightarrow 3.4 = 12$ ………….(2)
Now, putting 1 and 2 in the given expression, we will then obtain the following expression with us:-
$ \Rightarrow 15 - \dfrac{{35}}{7}.2 + 3.4 = 15 - 10 + 12$
Simplifying the right hand side of above expression by doing the calculations, we will then obtain the following expression with us:-
$ \Rightarrow 15 - \dfrac{{35}}{7}.2 + 3.4 = 17$
Hence, the required answer is 17.

Note: The students must note that we have used the underlying BODMAS rule in solving the above question.
BODMAS stands for Bracket, Of, Division, Multiplication, Addition and Subtraction.
We solve any equation in this sequence only.
Therefore, in the above question, we first multiplied the given quantities, then we did the addition and subtraction.