What is the value of $\dfrac{21w}{10}-w+1$ when $w=2$? 
Overseas Competition->Knowledge Point->Calculation Modules->Basic Concepts of Equation->Equivalent Substitution->Algebraic Expressions
When $w= 2$,  $$\frac{21w}{10}-w+1= \frac{21 \times 2}{10}-2+1$$  $$= \frac{42}{10}-2+1$$  $=4.2-2+1$  $= 2.2 + 1$  $= 3.2$. 