Working backwards

Siti gave away two fifths of her stickers and 6 more stickers to her cousin. She had 42 stickers left. How many stickers did she have at first? Try it first. Pause if you like. Start with all her stickers. The question says two fifths, so cut the bar into 5 equal parts. Two of them went to her cousin. Three parts are still hers. But 6 more stickers went as well. Here they are, off the end of what she kept. And look at the size of it. 6 stickers is not one of the parts. What's left after both is 42. So write what the 42 really is. Three units, minus 6, is 42. Now go backwards, and the 6 goes back first. Put those 6 back onto the end. 42 plus 6 is 48. So three parts hold 48 stickers. Three parts are 48, and there are 5 parts in all. 48 divided by 3 is one part. Times 5 for all 5 parts. 80. She had 80 stickers at first.