When teaching place value, I believe that it is truly important that students are able to rename a number. If they can do that, it shows the students' understanding of the number.
Here is what I mean by renaming. My example number is 253.
Students should be able to identify that 253 can be represented as:
253 ones
2 hundreds 5 tens 3 ones
2 hundreds 53 ones
2 hundreds 53 ones
25 tens 3 ones
As a challenge for my upper primary students, I asked them to rename whole numbers of six and seven digits. I organised this activity as a challenge between groups; the group that was able to rename the number in most amount of ways won. One point was allocated for every correct renaming of their numbers.
Although at first, it was a bit of a struggle, once groups got into it, they really impressed me with their skills. I also was able to see that some students need to work on their spelling on larger numbers. This was a great activity though to truly identify which students full understood place value.