# Borrow Exercises In this exercise, you'll learn how to borrow tokens from Aave V3. The starter code for this exercise is provided in `foundry/src/exercises/Borrow.sol` Solution is provided in `foundry/src/solutions/Borrow.sol` ## Task 1 - Approximate the maximum amount of token that can be borrowed ```solidity function approxMaxBorrow(address token) public view returns (uint256) { // Task 1.1 - Get asset price from the oracle. // The price is returned with 8 decimals (1e8 = 1 USD) // Task 1.2 - Get the decimals of token // Task 1.3 - Get the USD amount that can be borrowed from Aave V3 // Task 1.4 - Calculate the amount of token that can be borrowed } ``` Implement the `approxMaxBorrow(` function. This function will approximate the maximum amount of token that you can borrow. - `token` is the token to borrow > Hints > > - Call `oracle.getAssetPrice` to get the USD price of `token` > - Call `pool.getUserAccountData` to get the maximum USD amount that can be borrowed from Aave > - Approximate amount of `token` that can be borrowed is the max USD value that can be borrowed divide by the price of `token` ## Task 2 - Get the health factor of this contract ```solidity function getHealthFactor() public view returns (uint256) {} ``` Get the health factor of this contract > Hint - Call `pool.getUserAccountData` ## Task 3 - Borrow token from Aave V3 ```solidity function borrow(address token, uint256 amount) public {} ``` Borrow `token` from Aave V3 - `token` is the token to borrow - `amount` is the amount of `token` to borrow > Hint - Call `pool.borrow` ## Task 4 - Get variable debt balance of this contract ```solidity function getVariableDebt(address token) public view returns (uint256) { // Task 4.1 - Get the variable debt token address from the pool contract // Task 4.2 - Get the balance of the variable debt token for this contract. // Balance of the variable debt token is the amount of token that this // contract must repay to Aave V3. } ``` Get variable debt balance of this contract. > Hints > > - Call `pool.getReserveData` to get the address of variable debt token > - Query the balance of variable debt token for this contract to get the current debt that this contract owes to Aave ## Test ```shell forge test --fork-url $FORK_URL --fork-block-number $FORK_BLOCK_NUM --match-path test/Borrow.test.sol -vvv ```