Here is a great link to be able to understand how to decompose numbers a bit more!!  This is a great video to explain decomposing numbers and what that means

https://learnzillion.com/assignments/SY4KF2B

Take a look at this image – look at how you don’t only need to break apart by using place value, you can break apart by what makes the most sense to you!!  Notice how they all equal 43!