Let us discuss CBSE Sample Paper 201718 of Mathematics Class 10
There are 4 sections
Section  How many marks?  Number of Questions  Total Marks 
Section A  1 marks each  6  1 × 6 = 6 
Section B  2 marks each  6  2 × 6 = 12 
Section C  3 marks each  10  3 × 10 = 30 
Section D  4 marks each  8  4 × 8 = 32 
Total  80 
Marks per Chapter
According to CBSE Syllabus, the marks per unit is like this
Units  Chapters of NCERT  Marks  
I.  Number System  Chapter 1  6 
II.  Algebra  Chapter 2, 3, 4, 5  20 
III.  Coordinate Geometry  Chapter 7  6 
IV.  Geometry  Chapter 6, 10, 11  15 
V.  Trigonometry  Chapter 8, 9  12 
VI.  Mensuration  Chapter 12, 13  10 
VII.  Statistics & Probability  Chapter 14, 15  11 
Total  80 
In this sample paper, lets see how many questions of which chapter are asked
Chapter  1 Mark Questions  2 Mark Questions  3 Mark Questions  4 Mark Questions  Total Marks 
Chapter 1  1  1  1  6  
Chapter 2  1  3  
Chapter 3  1  1  5  
Chapter 4  1  1  5  
Chapter 5  1  1  1  7  
Chapter 6  1  1  1  8  
Chapter 7  1  1  1  6  
Chapter 8  1  1  1  8  
Chapter 9  1  4  
Chapter 10  1  3  
Chapter 11  1  4  
Chapter 12  1  3  
Chapter 13  1  1  7  
Chapter 14  1  1  7  
Chapter 15  2  4  
Total  80 
Points to be noted about marking

1 mark question has no step marking. If the answer is wrong, 1 mark is cut.

Writing units is important or half marks is cut, eg: x =3 is wrong, x = 3 metre is right.

Formula of all chapters has 1/2 marks

Formula of Statistics (Chapter 14) has 1 mark

In Chapter 9 Heights and Distances, 1 mark is given for correct figure

1 Question of Theorem will come. (Of Chapter 6 or 10)

1 4Marks question of Construction will come

In Construction Question  Writing steps has no marks, just make the figure
 NCERT Questions are very important  6 Questions out of 30 have come straight from NCERT. 3 Questions are similar to NCERT