Gas and transaction fees in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the gas limit for a transaction.

Blockchain / Solidity

transaction = {"to": recipient, "value": amount, "gas": [1]

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

A5000

B21000

C100000

D30000

Attempts:

3 left

💡 Hint

Common Mistakes

Using too low or too high gas limits causing transaction failure or waste.

The standard gas limit for a simple ETH transfer is 21000 units.

2fill in blank

medium

Complete the code to calculate the total transaction fee.

Blockchain / Solidity

total_fee = gas_price * [1]

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

Avalue

Bnonce

Cblock_number

Dgas_limit

Attempts:

3 left

💡 Hint

Common Mistakes

Multiplying gas price by nonce or value instead of gas limit.

The total fee is gas price multiplied by gas limit.

3fill in blank

hard

Fix the error in the code to set the gas price correctly.

Blockchain / Solidity

transaction['gasPrice'] = [1]

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

Agas_price

Bgasprice

CGasPrice

DgasPrice

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong case or misspelled variable names.

The correct variable name is gas_price matching the code context.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension for gas fees above a threshold.

Blockchain / Solidity

high_fees = {tx_id: tx['gasPrice'] * [1] for tx_id, tx in transactions.items() if tx['gasPrice'] [2] threshold}

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

Atx['gasLimit']

Btx['value']

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong keys or wrong comparison operators.

Calculate fee by multiplying gasPrice and gasLimit, filter fees greater than threshold.

5fill in blank

hard

Fill all three blanks to create a filtered dictionary of transactions with fees above a limit.

Blockchain / Solidity

filtered = {tx['from']: tx['gasPrice'] * [1] for tx in tx_list if tx['gasPrice'] [2] min_price and tx['gasLimit'] [3] max_limit}

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

Atx['gasLimit']

B>

C<

Dtx['value']

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up comparison operators or using wrong keys.

Calculate fee by gasPrice * gasLimit, filter gasPrice greater than min_price and gasLimit less than max_limit.