This number is: 24-3=2 1 or 24*2-3=45 ... It can be recorded as 24n-3(n stands for a natural number greater than 1).
Of course, for the third grade students, you can't say that.
Why don't you list it?
The number matching 6: 39152127 33 39 455157 63 69 7581. ......
Number matching 8: 5132129 37 45 53 6169. ......
This means that there are 2 1 45 69 eligible numbers. ......
The question "What is this number?" Is ambiguous, it should be "what is the minimum number?" "What will this number be?"