30 / 3 / 10= 1 or 9??

$1-10+3-20+5-30+7-40+9=\text{\_\_\_}$

Decimal form of $30+9+\frac{3}{10}+\frac{1}{100}$ is ___.

From each of the given pairs, find which ratio is larger:

(i) $(3:4)$ or $(9:16)$

(ii) $(5:12)$ or $(17:30)$

(iii) $(3:7)$ or $(4:9)$

(iv) $(1:2)$ or $(13:27)$