The farm track had a row of posts, each with a number. They went all the way to one hundred.

"Can I drive the tractor?" asked Little Thunder.

"Only with me beside you," said Spike. "Let's do number jumps."

They started at post twelve. "Add ten," said Suzy.

The tractor rumbled along. "Twenty-two!" said Little Thunder.

"Add ten again."

"Thirty-two!"

"See the pattern?" said Spike. "When you add ten, only the tens number changes."

Next they added ones. "Thirty-two, thirty-three, thirty-four." Small jumps, little bumps.

"Now take away ten," said Suzy. The tractor rolled backwards. "Twenty-four!"

Little Thunder grinned. "Big jumps for tens, small jumps for ones."

They jumped and bumped until they reached the last post. "One hundred!" everyone cheered.

Sydney the cow poked her head over the fence. "What are you all doing?"

"Maths," said Little Thunder proudly. "On a tractor!"

"That," said Sydney, "is the best kind of maths."