3 hundreds + 42 ones

 

After I completed the equation, I checked and saw the Khan Academy answers just for good measure. And the two answers were these:

• 3 hundreds + 42 tens
• 2 hundreds + 14 tens + 2 ones 

Now, one of these answers is incorrect, specifically the first one, 3 hundreds+ 42 tens. If you had 300 plus 42 tens, the answer would be 720, because 42 tens is 420. But, the intended answer was 342, so the actual correct answers would be: 

3 hundreds + 42 ones

2 hundreds + 14 tens + 2 ones

Thank you for reading, and if anyone at Khan Academy sees this, please correct it.