Ethereum Virtual Machine (EVM) in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a simple EVM bytecode sequence that stops execution.

Blockchain / Solidity

bytecode = [[1]]

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

A0x56

B0x60

C0xF3

D0x00

Attempts:

3 left

💡 Hint

Common Mistakes

Using PUSH1 (0x60) instead of STOP.

Using JUMP (0x56) which jumps to a location.

Using RETURN (0xF3) which returns data.

The opcode 0x00 is the STOP instruction in EVM, which halts execution.

2fill in blank

medium

Complete the code to push the value 0x05 onto the EVM stack.

Blockchain / Solidity

bytecode = [[1], 0x05]

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

A0x60

B0x01

C0x50

D0x56

Attempts:

3 left

💡 Hint

Common Mistakes

Using JUMP (0x56) instead of PUSH1.

Using POP (0x50) which removes from stack.

Using ADD (0x01) which adds top stack items.

The opcode 0x60 is PUSH1, which pushes the next 1 byte onto the stack.

3fill in blank

hard

Fix the error in the code to correctly add two numbers on the EVM stack.

Blockchain / Solidity

bytecode = [0x60, 0x03, 0x60, 0x04, [1]]

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

A0x50

B0x01

C0x02

D0x56

Attempts:

3 left

💡 Hint

Common Mistakes

Using JUMP (0x56) instead of ADD.

Using POP (0x50) which removes stack items.

Using MUL (0x02) which multiplies instead of adds.

The opcode 0x01 is ADD, which adds the top two stack values.

4fill in blank

hard

Fill both blanks to create bytecode that pushes 0x02 and 0x03, then multiplies them.

Blockchain / Solidity

bytecode = [[1], 0x02, [2], 0x03, 0x02]

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

A0x60

B0x01

D0x03

Attempts:

3 left

💡 Hint

Common Mistakes

Using ADD (0x01) or MUL (0x02) instead of PUSH1 for pushing values.

Mixing up opcodes for pushing and arithmetic.

Both 0x60 opcodes push 1 byte values (0x02 and 0x03) onto the stack before multiplication.

5fill in blank

hard

Fill all three blanks to push 0x04 and 0x05, add them, then stop execution.

Blockchain / Solidity

bytecode = [[1], 0x04, [2], 0x05, 0x01, [3]]

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

A0x60

B0x01

C0x00

D0x50

Attempts:

3 left

💡 Hint

Common Mistakes

Using POP (0x50) instead of STOP.

Forgetting to push both values.

Using wrong opcode for addition or stop.

Use PUSH1 (0x60) twice to push 0x04 and 0x05, then ADD (0x01) to add them, and STOP (0x00) to end execution.