divide and conquer
US /dɪˈvaɪd ænd ˈkɑːŋkər/
UK /dɪˈvaɪd ænd ˈkɑːŋkər/

1.
a strategy of breaking a large problem or task into smaller, more manageable parts to solve them more easily, or a political strategy of maintaining control over a population by encouraging internal divisions and conflicts
:
•
To tackle the complex project, we decided to divide and conquer by assigning different teams to specific modules.
•
The dictator used a divide and conquer strategy to prevent any unified opposition from forming.