‘How Many Additional Blocks’ Riddle Answer: How to Make the Cube Whole


Many riddles and puzzles are circulating these days while people are sheltering at home during the coronavirus pandemic. One of the many puzzles being shared on social media sites like Instagram, Facebook, and Twitter is the “how many additional blocks” puzzle. Read on to learn more about the answer and the puzzle.

The puzzle’s question typically reads like this:

How many additional blocks are required to make the cube whole? (Assume the hidden inside cubes are there.)


This is tricky, and people answering the puzzle are sometimes debating on just what the right answer should be. Are you ready to learn the answer? Read on for more details.

Here’s the Answer

The answer is 45. 

Read the question closely. It’s asking how many blocks are needed to make the cube whole. The trick is that the definition of a cube is a symmetrical three-dimensional shape. The block in the picture has a height of 4 cubes and a width and depth of 5 cubes. So in order to create a cube, you would need to add a 5×5 layer to the top or bottom, in addition to filling in the blank spaces.

You’ll need 20 cubes to fill in the blank spaces, but that’s not enough to meet the requirements of the puzzle. To create a new 5×5 layer, you need 25 additional cubes. Since 20+25=45, you’ll need 45 cubes total to create a cube that’s whole (assuming there are no missing cubes inside the block that we can’t see.)

Here’s the Answer to a Similar Puzzle with the Same Picture, But Worded Differently

Another slightly different version of this puzzle shows the same picture but asks:

How many cubes would be needed to fill the larger block?

For this version, you can assume the answer is simply 20. That’s because the slightly altered question is asking to fill the block, not the cube. A block doesn’t need equal sides. Only 20 smaller cubes are needed to fill the empty spaces in the block we’re seeing in this picture.

This version of the puzzle was discussed on Reddit here. One person suggested 20 and another replied: “I think you’re correct, the question posted asks you to fill the larger block, not larger cube. A block doesn’t have to have equal sides.” 

And as another pointed out: “Yeah I think you’re right, it’s either 20 if you are just filling it in, or 45 if you are making the whole cube.”

It all depends on how the question is worded. If you’re asked to make the cube whole, then the answer is 45. If you’re asked to make the block whole, then the answer is 20.

This is just one of many riddles and puzzles that are circulating on sites like Facebook and Instagram during the coronavirus pandemic. If you’ve seen the “How Many Ducks Do You See?” riddle and were stumped, check out Heavy’s explanation here. If you ran into the “I Met a Man on London Bridge” riddle and have no idea what the man’s name is, you can find the answer in Heavy’s story here. The answer to the “You Enter a Bedroom” riddle is here, and the answer to the “Can You Open the Lock Using These Clues?” riddle is here.

If you’re looking for the answer to the “Hotel with 100 Rooms” riddle, it’s here. The answer to the “State Without an A” riddle is here. The answer to the “How many letters are in the answer?” riddle is here. And the answer to the “Penny Has 5 Children” riddle is here.

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