# Position Manager Exercises In this exercise, you'll learn how to use the [`PositionManager`](https://github.com/Uniswap/v4-periphery/blob/main/src/PositionManager.sol) contract. The starter code for this exercise is provided in [`foundry/src/exercises/Posm.sol`](https://github.com/Cyfrin/defi-uniswap-v4/blob/main/foundry/src/exercises/Posm.sol) Solution is in [`foundry/src/solutions/Posm.sol`](https://github.com/Cyfrin/defi-uniswap-v4/blob/main/foundry/src/solutions/Posm.sol) ## Task 1 - Increase liquidity ```solidity function increaseLiquidity( uint256 tokenId, uint256 liquidity, uint128 amount0Max, uint128 amount1Max ) external payable { // Write your code here } ``` Complete the function to increase liquidity for the position identified by `tokenId`. ## Task 2 - Decrease liquidity ```solidity function decreaseLiquidity( uint256 tokenId, uint256 liquidity, uint128 amount0Min, uint128 amount1Min ) external { // Write your code here } ``` Complete the function to decrease liquidity for the position identified by `tokenId`. ## Task 3 - Burn ```solidity function burn(uint256 tokenId, uint128 amount0Min, uint128 amount1Min) external { // Write your code here } ``` Complete the function to burn the position identified by `tokenId`. ## Test ```shell forge test --fork-url $FORK_URL --match-path test/Posm.test.sol -vvv ```