Yield farming concepts in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a function that returns the annual percentage yield (APY) given a simple interest rate.

Blockchain / Solidity

function calculateAPY(rate) {
  return (1 + [1]) ** 1 - 1;
}

Drag options to blanks, or click blank then click option'

Arate

Brate * 100

Crate / 100

Drate + 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using the rate directly without dividing by 100 causes wrong APY calculation.

The interest rate must be converted from a percentage to a decimal by dividing by 100 before calculating APY.

2fill in blank

medium

Complete the code to calculate the total rewards earned by multiplying staked tokens by the reward rate.

Blockchain / Solidity

function calculateRewards(stakedTokens, rewardRate) {
  return stakedTokens [1] rewardRate;
}

Drag options to blanks, or click blank then click option'

A/

B+

C-

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition or subtraction instead of multiplication.

Rewards are calculated by multiplying the amount staked by the reward rate.

3fill in blank

hard

Fix the error in the code that calculates compounded yield over multiple periods.

Blockchain / Solidity

function compoundedYield(principal, rate, periods) {
  return principal * (1 + [1]) ** periods;
}

Drag options to blanks, or click blank then click option'

Arate / 100

Brate * 100

Crate + 1

Drate - 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using the rate directly without conversion causes incorrect yield.

The rate must be converted from a percentage to a decimal by dividing by 100 before compounding.

4fill in blank

hard

Fill both blanks to create a filtered object that maps token names to their staked amounts if the amount is greater than zero.

Blockchain / Solidity

const stakedTokens = Object.fromEntries(Object.entries(tokens).filter(([[1], [2]]) => [2] > 0 ));

Drag options to blanks, or click blank then click option'

Atoken

Bamount

Ctokens

Dtoken.toUpperCase()

Attempts:

3 left

💡 Hint

Common Mistakes

Using the whole tokens object as key or value.

The object maps each token name to its staked amount, filtering only positive amounts.

5fill in blank

hard

Fill all three blanks to create a function that returns a filtered object of tokens with APY greater than a threshold.

Blockchain / Solidity

function filterHighAPY(tokens, threshold) {
  return Object.fromEntries(Object.entries(tokens).filter(([[1], [2]]) => [3] > threshold));
}

Drag options to blanks, or click blank then click option'

Atoken

Bapy

Camount

Drate

Attempts:

3 left

💡 Hint

Common Mistakes

Using amount or rate instead of apy for filtering.

The function filters tokens by checking if their APY is greater than the threshold.

Practice

1. What is the main purpose of yield farming in blockchain?

easy

A. To trade cryptocurrencies on exchanges

B. To earn rewards by staking cryptocurrency in pools

C. To mine new cryptocurrency coins

D. To create new blockchain networks

Solution

1. Step 1: Understand yield farming basics

   Yield farming involves staking crypto assets to earn rewards.

2. Step 2: Compare options to yield farming

   Mining, trading, and creating blockchains are different activities.

3. Final Answer:

   To earn rewards by staking cryptocurrency in pools -> Option B

4. Quick Check:

   Yield farming = earning rewards by staking [OK]

Hint: Yield farming means staking crypto to earn rewards [OK]

Common Mistakes:

• Confusing yield farming with mining
• Thinking yield farming is trading
• Believing yield farming creates new blockchains

2. Which of the following is the correct way to describe a yield farming pool?

easy

A. A software to trade cryptocurrencies instantly

B. A wallet to store cryptocurrencies securely

C. A blockchain that creates new tokens automatically

D. A place where users stake crypto to earn rewards

Solution

1. Step 1: Define a yield farming pool

   A pool is where users stake crypto to earn rewards.

2. Step 2: Eliminate unrelated options

   Wallets store crypto, blockchains create tokens, and software trades crypto.

3. Final Answer:

   A place where users stake crypto to earn rewards -> Option D

4. Quick Check:

   Pool = staking place for rewards [OK]

Hint: Pools are for staking crypto to earn rewards [OK]

Common Mistakes:

• Mixing pools with wallets
• Thinking pools create tokens
• Confusing pools with trading software

3. Consider this simplified code snippet for calculating yield farming rewards:

def calculate_rewards(staked_amount, reward_rate):
    return staked_amount * reward_rate

print(calculate_rewards(1000, 0.05))

What is the output of this code?

medium

A. 50.0

B. 5

C. 1000

D. 0.05

Solution

1. Step 1: Understand the function calculation

   The function multiplies staked_amount (1000) by reward_rate (0.05).

2. Step 2: Calculate the multiplication

   1000 * 0.05 = 50.0

3. Final Answer:

   50.0 -> Option A

4. Quick Check:

   1000 * 0.05 = 50 [OK]

Hint: Multiply staked amount by reward rate [OK]

Common Mistakes:

• Confusing multiplication with addition
• Using reward rate as output directly
• Mixing up staked amount and reward rate

4. Find the error in this yield farming reward calculation code:

def calculate_rewards(staked_amount, reward_rate):
    rewards = staked_amount + reward_rate
    return rewards

print(calculate_rewards(1000, 0.05))

medium

A. Incorrect function name

B. Missing return statement

C. Using addition instead of multiplication for rewards

D. Wrong print syntax

Solution

1. Step 1: Review the reward calculation logic

   The code adds staked_amount and reward_rate instead of multiplying.

2. Step 2: Understand correct reward formula

   Rewards should be staked_amount * reward_rate, not addition.

3. Final Answer:

   Using addition instead of multiplication for rewards -> Option C

4. Quick Check:

   Rewards = stake * rate, not stake + rate [OK]

Hint: Rewards = stake times rate, not plus rate [OK]

Common Mistakes:

• Adding instead of multiplying rewards
• Forgetting to return value
• Misnaming functions
• Incorrect print usage

5. You want to calculate total rewards from multiple pools with different stakes and rates:

pools = {"PoolA": (1000, 0.05), "PoolB": (2000, 0.03), "PoolC": (1500, 0.04)}
total_rewards = sum(stake * rate for stake, rate in pools.values())
print(total_rewards)

What is the output of this code?

hard

A. 170.0

B. 0.12

C. 4500

D. SyntaxError

Solution

1. Step 1: Calculate rewards for each pool

   PoolA: 1000*0.05=50, PoolB: 2000*0.03=60, PoolC: 1500*0.04=60

2. Step 2: Sum all rewards

   Total = 50 + 60 + 60 = 170

3. Step 3: Verify code output

   The code prints the sum of rewards, which is 170.0 (float)

4. Final Answer:

   170.0 -> Option A

5. Quick Check:

   Sum of all pool rewards = 170.0 [OK]

Hint: Sum stake * rate for each pool to get total rewards [OK]

Common Mistakes:

• Adding rates instead of multiplying
• Forgetting to sum all pools
• Expecting integer output instead of float
• Misreading dictionary values