In a stall, some mini-helicopters and jigsaw puzzles were on sale. ¹₄ of the items were mini-helicopters. ²₃ of the mini-helicopters and 78 jigsaw puzzles were sold. There were ¹₉ of the items left in the stall. How many mini-helicopters and jigsaw puzzles were there in the stall at first?

	Mini-helicopters	Jigsaw puzzles	Total
Comparing mini-helicopters  and jigsaw puzzles at first	1x9 = 9 u	3x9 = 27 u	4x9 = 36 u
Before	3x3 =  9 u		9x4 = 36 u
Change	- 2x3 = - 6 u	- 78	- 8x4 = - 32 u
After	1x3 = 3 u	1 u	1x4 = 4 u

 
The total number of toys at first is repeated.  Make the total number of toys at first the same. LCM of 4 and 9 is 36.

The number of mini-helicopters at first is repeated.  Make the number of mini-helicopters the same. LCM of 9 and 3 is 9. 

Number of jigsaw puzzles left
= 4 u - 3 u
= 1 u

Number of jigsaw puzzles sold
= 27 u - 1 u
= 26 u

26 u = 78

1 u = 78 ÷ 26 = 3

Number of mini-helicopters and jigsaw puzzles at first
= 36 u
= 36 x 3
= 108

Answer(s): 108