This helps with understanding how place value works as the figures move and the decimal point stays still when multiplying by powers of 10. Also useful for seeing how each 5 is related to another 5 in a different row. Useful also to show how Billions (1000 Million in UK since Harold Wilson’s time) are related to Thousands etc.
ActivInspire flipchart available Multiplying by Powers of 10 as well as a pdf file: Multiplying by Powers of 10.
Also available a more extensive flipchart is here.