Real life examples of math around us

Today we started a new programme in our maths time:

looking at real life examples of maths.  

We looked at a photo and brainstormed all the maths questions we might have about that photo.  Mrs Griffin recently laid some ready lawn at her house, so she showed us a photo of a pallet of ready lawn.  We discussed what ready lawn is and what a pallet is.  We know that people use pallets to carry things around with forklifts.
We had lots of questions about this pallet of grass.  
Here are some of our questions:
How much does it weigh?
How many rolls on the pallet?
How long are they rolled out?
How many rolls to fill a paddock?
How many rows altogether?
How many could you put on the pallet?
How tall is the stack?
What area would it cover?

Mrs Griffin told us that one pallet weighs one tonne - about the same weight as Mrs Francis' truck (which we can see from our class).  We tried to figure out how much that might be in kilograms.  We discussed what we know about the metric system and weight.  We know the metric system works in 1, 10, 100, 1000, 10,000 like place value.
We know one litre of water weighs 1kg.  We know this because we weighed a litre of water during our maths stations earlier this term.  Then we considered our own weight which varies in our class, but we figured that if someone in our class weighs 30kg then a tonne can't be 10kg.  Then we looked at 100kg and we ruled that out too, because we know that rugby players can weigh more than 100kg; we didn't think that rugby players would be as heavy as Mrs Francis' truck.  So we concluded that one tonne must be 1000kg.
Phew, that was a lot of maths discussion, but we weren't finished.  We decided to figure out how many rolls were on the pallet.  Ngaio suggested we could count in 3s because there are 3 in each row.  So we counted the top row and realised there were 15 rolls.  Carter said we could multiply that by 4 because there were 4 layers of 15 rolls.  We decided to use some repeated addition, we could add 15+15 which equals 30 and then add 30 to get 60 rolls altogether.  We also looked at the way we could use some of our multiplication facts to work it out.  If we know our 10 and 5 times tables we can multiple 4x10 and 4x5 and add them together.
Wow, that was some great multiplicative thinking.  Now we tried to figure how much one roll of ready lawn might weigh.  We looked at our checklist for problem solving and the first thing we needed was a plan.  Some of us worked in groups and some worked independently to try and solve this problem.  We knew there were 60 rolls and they weighed 1000kg.  Can you figure out how much one roll weighs?