4th Grade Place Value Riddles

So I got the news it looks likely I am being switched to 4th grade for summer school. Not a huge deal since I taught it last summer but I thought I was teaching the younger ones. Oh well.

To switch gears, I made this new Boom Card deck with 400 cards to practice place-value to the millions. 
There are 4 riddles and every time they answer a question, a new letter in the answer is revealed. 

The skills included are:
1. Comparing using <,=>
2. Identifying the place value digit
3. Expanded form
4. Rounding 

For each correct answer, the student earns a letter to the riddle solution. 

CCSS.MATH.CONTENT.4.NBT.A.2

Read and write multi-digit whole numbers using base-ten numerals, number names, and expanded form. Compare two multi-digit numbers based on meanings of the digits in each place, using >, =, and < symbols to record the results of comparisons.

CCSS.MATH.CONTENT.4.NBT.A.3

Use place value understanding to round multi-digit whole numbers to any place.

These are available in my TpT store or Boom Learning store.

Is anyone else teaching summer school? I miss having the whole summer off but now that I have 2 in college I can't afford to say no. I still get about 6 weeks off so it isn't too terrible.