Download App

Algebraic Expressions and Identities — MATHS STD 8 — Question

Gujarat BoardEnglish MediumSTD 8MATHSAlgebraic Expressions and Identities1 Mark
MCQ
Evaluate $4.5 \times 3.5$ using a suitable identity.
  • A
    $1575$
  • ✓
    $15.75$
  • C
    $16.25$
  • D
    $16$
✓

Answer

Correct option: B.
$15.75$
B.  $15.75$
Solution:
We can write $4.5 \times 3.5$ as $(4+0.5) \times(4-0.5)$
Using $(a+b)(a-b)=a^2-b^2$, we get
$4.5 \times 3.5=(4+0.5) \times(4-0.5)=4^2-(0.5)^2 $
$=16-0.25=15.75$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q. [1 Marks Each]" from Algebraic Expressions and Identities→Algebraic Expressions and Identities — all question types→MATHS STD 8 question papers→Gujarat Board STD 8 question papers→Gujarat Board question paper generator→

Similar questions

Mark $(\checkmark)$ against the correct answer of the following:$\frac{4}{3}\div\ ?=\frac{-5}{2}$
→
Tick $(\checkmark)$ the correct answer:
Number of boys and girls in a class are in the ratio $7 : 5.$ The number of boys is 8 more than the number of girls. The total class strength is:
→
If an angle of a parallelogram is two-thirds of its adjacent angle, the smallest angle of the parallelogram is:
→
If a cuboidal box has height, length and width as $20\ cm, 15\ cm$ and $10\ cm$ respectively. Then its total surface area is:
→
What is the square root of $5929?$
→
Mark $(\checkmark)$ against the correct answer of the following: $\Big(\frac{-5}{4}\Big)^{-1}=\ ?$
→
The compound interest on ₹ 40000 at $6 \%$ per annum for 6 months, compounded quarterly. Is
→
The square of a natural number subtracted from its cube is $48$. The number is:
→
What per cent of 90 is $120 ?$
→
The area of a trapezium is $480\ cm^2$, the distance between two parallel sides is $15\ cm$ and one of the parallel side is $20\ cm.$ The other parallel side is:
→