List of top Mathematics Questions asked in CBSE Class VIII

(a) Simplify 3x (4x – 5) + 3 and find its values for (i) x = 3 (ii) x =\(\frac{1}{2}\)
(b) Simplify a (a²+ a + 1) + 5 and find its value for (i) a = 0, (ii) a = 1 (iii) a = – 1.

Subtract 4p²q – 3pq + 5pq² – 8p + 7q – 10 from 18 – 3p – 11q + 5pq – 2pq² + 5p²q

Simplify.
(i) (x²– 5) (x + 5) + 25
(ii) (a²+ 5) (b³+ 3) + 5
(iii) (t + s²)(t² – s)
(iv) (a + b) (c – d) + (a – b) (c + d) + 2 (ac + bd)
(v) (x + y) (2x + y) + (x + 2y) (x – y)
(vi) (x + y) (x²– xy + y²)
(vii) (1.5x – 4y) (1.5x + 4y + 3) – 4.5x + 12y
(viii) (a + b + c) (a + b – c)

Describe how the two figures at the right are alike and how they are different. Which box has larger lateral surface area?

box

Find the product.
(i) (5 – 2x) (3 + x)
(ii) (x + 7y) (7x – y)
(iii) (a²+ b) (a + b²)
(iv) (p² – q²) (2p + q)

Length of the fence of a trapezium shaped field ABCD is 120 m. If BC = 48 m, CD = 17 m and AD = 40 m, find the area of this field. Side AB is perpendicular to the parallel sides AD and BC.

Diagram of the adjacent picture frame has outer dimensions = 24 cm x 28 cm and inner dimensions 16 cm x 20 cm. Find the area of each section of the frame, if the width of each section is same.

section of frame

Add the following. l² + m², m² + n², n² + l², 2lm + 2mn + 2nl

Subtract 3xy + 5yz – 7zx from 5xy – 2yz – 2zx + 10xyz

Find the number of digits in the square root of each of the following numbers (without any calculation).

64
144
4489
27225
390625

Subtract 4a – 7ab + 3b + 12 from 12a – 9ab + 5b – 3

Add the following. a – b + ab, b – c + bc, c – a + ac.

\(\frac{ (8^{−1}× 5^3)}{2^{−4}} \)
\((5^{−1}× 2^{−1})×6^{−1}\)

\(x^ 2 + xy + 8x + 8y\)
\(15xy - 6x + 5y - 2 \)
\(ax + bx - ay - by\)
\(15pq + 15 + 9q + 25p\)
\(z - 7 + 7xy - xyz\)

Find the least number which must be subtracted from each of the following numbers so as to get a perfect square. Also find the square root of the perfect square so obtained.

402
1989
3250
825
4000

For each of the following numbers, find the smallest whole number by which it should be divided so as to get a perfect square number. Also find the square root of the square number so obtained.

252
2925
396
2645
2800
1620

Factorise the expressions

\(ax^2 + bx\)
\(7p^ 2 + 21q^ 2\)
\(2x^ 3 + 2xy^2 + 2xz^2\)
\(am^2 + bm^2 + bn^2 + an^2\)
\((lm + l) + m + 1\)
\(y(y + z) + 9(y + z)\)
\(5y^ 2 - 20y - 8z + 2yz\)
\(10ab + 4a + 5b + 2\)
\(6xy - 4y + 6 - 9x\)

Complete the following table of products:

First monomial → Second monomial ↓	2x	–5y	3x²	– 4xy	7x² y	–9x² y²
2x	4x²	. . .	. . .	. . .	. . .	. . .
–5y	. . .	. . .	-15x²y	. . .	. . .	. . .
3x²	. . .	. . .	. . .	. . .	. . .	. . .
– 4xy	. . .	. . .	. . .	. . .	. . .	. . .
7x² y	. . .	. . .	. . .	. . .	. . .	. . .
–9x² y²	. . .	. . .	. . .	. . .	. . .	. . .

Solve the linear equation: \(\frac{3t-2}{4}-\frac{2t+3}{3}=\frac{2}{3}-t\)

Add the following.2p²q² – 3pq + 4, 5 + 7pq – 3p²q.

Factorise the following expressions

\(7x - 42\)
\(6p - 12q\)
\(7a ^2 + 14a\)
\(-16z + 20z ^3\)
\(20l^ 2m + 30\, alm\)
\(5x^ 2 y - 15xy^2\)
\(10a^ 2 - 15b^ 2 + 20c^ 2 \)
\(-4a^ 2 + 4ab - 4 ca\)
\(x ^2 yz + xy^2 z + xyz^2\)
\(ax^2 y + bxy^2 + cxyz\)

Draw a pie chart showing the following information. The table shows the colours preferred by a group of people.

Colours	Number of people
Blue	18
Green	9
Red	6
Yellow	3
Total	36

Factorise the following expressions.

\(a^ 2 + 8a + 16 \)
\(p^ 2 - 10p + 25 \)
\(25m^2 + 30m + 9 \)
\(49y^ 2 + 84yz + 36z ^2 \)
\(4x^ 2 - 8x + 4 \)
\(121b ^2 - 88bc + 16c ^2 \)
\((l + m) ^2 - 4lm \) (Hint: Expand \((l + m) ^2 \) first)
\(a^ 4 + 2a ^2b ^2 + b^ 4\)

(a) Add: p ( p – q), q ( q – r) and r ( r – p)
(b) Add: 2x (z – x – y) and 2y (z – y – x)
(c) Subtract: 3l (l – 4 m + 5 n) from 4l (10 n – 3 m + 2 l)
(d) Subtract: 3a (a + b + c) – 2 b (a – b + c) from 4c (– a + b + c)

The adjoining pie chart gives the marks scored in an examination by a student in Hindi, English, Mathematics, Social Science and Science. If the total marks obtained by the students were 540, answer the following questions:

pie chart gives the marks scored in an examination by a student in Hindi, English, Mathematics, Social Science and Science

In which subject did the student score 105 marks? (Hint: for 540 marks, the central angle = 360°. So, for 105 marks, what is the central angle?)
How many more marks were obtained by the student in Mathematics than in Hindi?
Examine whether the sum of the marks obtained in Social Science and Mathematics is more than that in Science and Hindi. (Hint: Just study the central angles).

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