The vegie patch had gone wild. There were pumpkins, carrots, and so many buckets of milk that the dairy was full.

"Let's measure everything for the harvest fair," said Suzy.

First, the pumpkins. Spike rolled the biggest one onto the scales. The needle swung around and stopped.

"Three kilograms and five hundred grams," read Suzy.

"How many grams is that altogether?" asked Little Thunder.

"There are one thousand grams in a kilogram," said Spike. "So three kilograms is three thousand grams. Add five hundred. Three thousand five hundred grams."

"That sounds much heavier," said Little Thunder.

"Same pumpkin," laughed Suzy. "Different units."

Next, the carrots. Little Thunder lined one up against the ruler. "Twenty-two centimetres! The longest carrot in the patch!"

Then the milk. Lima the cow had filled a big jug right up to a line. Spike crouched down so his eyes were level with it. "You have to read it at eye level, or it looks wrong. It says two thousand millilitres."

"And a thousand millilitres is one litre," said Suzy. "So two litres."

Little Thunder frowned. "Grams and kilograms. Millilitres and litres. It's always a thousand!"

"That's what milli and kilo mean," said Spike. "Kilo means a thousand. Milli means one-thousandth."

At the fair, Lima's milk won a ribbon. The long carrot won a ribbon. And Little Thunder carried the pumpkin to the judges, who weighed it again.

"Three point five kilograms," said the judge.

"That's three thousand five hundred grams," said Little Thunder confidently.

The judge was so impressed that she gave him a ribbon too, for the best measuring.