Level 3 Tiffany, Liam and Andy have a total of 189 erasers. Tiffany and Andy have a total of 110 erasers while Liam and Andy have a total of 137 erasers. How many more erasers does Andy have than Tiffany?
Level 2
Serene and Tommy have a total of 130 sweets. Tommy and Clara have a total of 141 sweets. Serene and Clara have a total of 99 sweets. How many sweets does Serene have?