Answer:

Across:

2: Add digits of 4 down

Answer:

there are 9000 four digit numbers in all

5: Shuffled digits of 2 across

Answer:

504

7: 4 down plus 2 down

Answer:

8889

Down

1: Two digits

Answer:

2-digit numbers are the numbers that have two digits and they start from the number 10 and end on the number 99

2: 1 down plus 4 down

Answer:

2

3: 4 times 4 down

Answer:

1

4: Ascending consecutive digits

Answer:

When we arrange them in ascending order, we can see that the difference between them is always 2

6: 2 down plus 5

3