Laziness? I didn't like remembering to carry when multiplying 45x16 so I did 40x16 + 5x16 - easy to add two numbers in your head, hard to remember two shifted p

Laziness? I didn't like remembering to carry when multiplying 45x16 so I did 40x16 + 5x16 - easy to add two numbers in your head, hard to remember two shifted partial results (the way it's done on paper). Different media require different methods. 45x 16 on paper: 270+ 45 It's easy to see here but in your head you have to remember that 45 is shifted left when added to 270. Visually it makes sense but otherwise hard. Breaking things into multiplications by 10, five or other easy substeps is recursive and easy to trace back up. Truth is I don't know how I came up with it, I think I was just lazy.