9.8 × 10.2 - Vidyadip

Question

$9.8 × 10.2$

✓

Answer

Here, we will use the identity $(a - b) (a + b) = a^2- b^2$
Let us consider the following expression:
$9.8 × 10.2$
$\because\frac{9.8+10.2}{2}=\frac{20}{2}=10,$therefore, we will write the above product as:
$9.8 × 10.2$
$= (10 - 0.2) (10 + 0.2)$
$= (10)^2- (0.2)^2$
$= 100 - 0.04$
$= 99.96$
Thus, the answer $99.96$

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 "3 Marks Question" 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

The amount of extension in an elastic string varies directly as the weight hung on it. If a weight of $150\ gm$ produces an extension of $2.9\ cm$, then what weight would produce an extension of $17.4\ cm?$

Divide $6 x^3-x^2-10 x-3$ by $2 x-3$ and find the quotient and remainder.

Solve:
$ a^4-16(b-c)^2$

A running track has $2$ semicircular ends of radius 63m and two straight lengths. The perimeter of the track is $1000\ m$. Find each straight length.

Find the square root of the following correct to three places of decimal:
$2.5$

Factorize:
$2L^2mn - 3Lm^2n + 4Lmn^2$

Take away: $\frac{\text{y}^3}{3}+\frac{7\text{y}^2}{3}+\frac{1}{2}\text{y}+\frac{1}{2}$ from $\frac{1}{3}−\frac{5}{3}\text{y}^2$

The students of Class $VIII$ of a school donated ₹ $2401$ for Prime Minister's National Relief Fund. Each student donated as many rupees as the number of students in the class. Find the number of students in the class.

Find the value of using the short-cut method: $(47)^3$

Find the smallest number by which $192$ must be divided to obtain a perfect cube.