Question

ADDING AND SUBTRACTING IN SCIENTIFIC NOTATION

Find the sum or difference.

$(7.8\times {10}^7)–(2.45\times {10}^6)$

Answer 1

Taking ${10}^6$ as common factor from the given expression we get,

$(7.8\times {10}^7)–(2.45\times {10}^6)$

$={10}^6\times (7.8\times 10–2.45)$

$={10}^6\times (78–2.45)$ (Solving subtraction in the bracket)

$={10}^6\times (75.55)$

$={10}^6\times (7.555\times 10)$

$=7.555\times 10\times {10}^6$ ( using exponent law ${\mathrm{a}}^{\mathrm{m}}\times {\mathrm{a}}^{\mathrm{n}}={\mathrm{a}}^{\mathrm{m}+\mathrm{n}}$)

$=7.555\times {10}^7$ ( Writing the number as scientific notation)