Predict: I predict this will involve decimals
Read: which will cost less per litre A)75c for 500ml B)2$ For 2 litres
Solve: I started with letter B half of 2 dollars is 1 and half of 2 litres is 1 so be would workout to be $1.00 and A would workout to be $1.50.
Mathematicians toolbox: I used guess, check and improve
Summery: my final answer was B