Count in 100s from 45. Stop on a number before you pass 1000. Decompse your number into hundreds, tens and ones

Step 1: Start at $45$ and add $100$ repeatedly.

$45 + 100 = 145$

Step 2:

$145 + 100 = 245$

Step 3:

$245 + 100 = 345$

Step 4:

$345 + 100 = 445$

Step 5:

$445 + 100 = 545$

Step 6:

$545 + 100 = 645$

Step 7:

$645 + 100 = 745$

Step 8:

$745 + 100 = 845$

Step 9:

$845 + 100 = 945$

Step 10: Next addition: $945 + 100 = 1045$, which passes $1000$, so stop at $945$.

Decomposed number: $945$

$945 = 9 \times 100 + 4 \times 10 + 5 \times 1$

$945 = 900 + 40 + 5$

900 + 40 + 5