Work out (47.6 × 10⁻⁵ × 13.7 × 10⁻¹)/(14.3 × 10⁻⁷) in standard form

Water sources: surface water (rivers, lakes), groundwater (wells, boreholes), rainwater harvesting. Nigeria has abundant water resources but distribution and quality vary. North is drier; south has more rainfall.

Uses: domestic (drinking, washing), agriculture (irrigation), industry, hydroelectric power. Growing population and economy increase demand. Major rivers: Niger, Benue, Cross River. Lake Chad shrinking.

Challenges: access to clean water (many lack), pollution, saltwater intrusion in coastal areas, seasonal variation, infrastructure decay. Water management crucial for health, food security, and development.