Use the product (a + b) (a – b) = a^2 – b^2 to evaluate : 7.7 8.3 - Vidyadip

Question

Use the product $(a + b) (a – b) = a^2 – b^2$ to evaluate : $7.7 \times 8.3$

✓

Answer

$7.7 \times 8.3 $
$= (8−0.3) (8+0.3)$
$= (8)^2− (0.3)^{2 }$
$= 64 − 0.09$
$= 63.91$

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 "[4 marks sum]" from Identities→Identities — all question types→MATHS STD 8 question papers→ICSE Board STD 8 question papers→ICSE Board question paper generator→

Similar questions

A man completed a trip of $136\ km$ in $8$ hours. Some part of the trip was covered at $15\ km/hr$ and the remaining at $18\ km/hr$. Find the part of the trip covered at $18\ km/hr.$

If $2 \mathrm{a}+\frac{1}{2 \mathrm{a}}=8$, find $: 4 \mathrm{a}^2+\frac{1}{4 \mathrm{a}^2}$

Find $(m+n) \div(m-n)$, if: $m =\frac{4}{5}$ and $n =-\frac{3}{10}$

The following table shows the market position of different brands of tea$-$leaves.

Brand	$A$	$B$	$C$	$D$	others
$\%$ of Buyers	$35$	$20$	$20$	$15$	$10$

Draw it pie$-$chart to represent the above information.

If $\mathrm{m}-\frac{1}{\mathrm{~m}}=5$, find: $\mathrm{m}^2-\frac{1}{\mathrm{~m}^2}$

In a quadrilateral $ABCD, AO$ and $BO$ are bisectors of angle $A$ and angle $B$ respectively . Show that : $\angle AOB = `1/2`$ $(\angle C + \angle D)$

Evaluate : $(a + bc) (a − bc) (a^2 + b^2c^2)$

Find the quotient and remainder : $\left(3 t^5+7 t^4-11 t^3+8 t^2-32 t+5\right)$ is divided by $\left(2+3 t+t^2\right)$

A dealer in Bihar supplied goods to a dealer in Mumbai. The dealer in Mumbai buys :$(i)\ 40$ articles for $800$ each at $30\%$ discount$ (ii)\ 75$ articles for $1,000$ each at $20\%$ discount.If the rate of $\text{GST}$, on the whole, is $12\%$, find how much will the dealer at Mumbai pay to a dealer in Bihar.

In order to complete a work in $28$ days, $60$ men are required. How many men will be required if the same work is to be completed in $40$ days?