Question

Expanded form of $243.7=(2\times {10}^2)+(4\times {10}^1)+$ + $(7\times {10}^{-1}$)

• A. $(3\times {10}^0)$
• B. $(3\times {10}^2)$
• C. $(3\times {10}^1)$
• D. $(4\times {10}^1)$

Answer 1

The correct option is A $(3\times {10}^0)$

Using $a^0=1$ and $a^{-m}=\frac{1}{a^m}$ for a non-zero integer $a$ and any integer $m,$ we have
$243.7=200+40+3+0.7$
$=(2\times {10}^2)+(4\times {10}^1)+(3\times {10}^0)+\frac{7}{10}$
$=(2\times {10}^2)+(4\times {10}^1)+(3\times {10}^0)+(7\times {10}^{-1}).$