Christoph Rudolff (1499 - 1545) was the author of the first German textbook on algebra. He introduced the symbol (√) for the square root. It is believed that this was because it resembled a lowercase "r" (for "radix"), though there is no direct evidence.
POWERS AND ROOTS
Does the square root of a negative number exist?
Key questions
Do we recognise the square numbers?
Can we problem solve with square numbers?
What does it mean to find the power of a number?
What does it mean to find the root of a number?
Can we problem solve with roots and powers?
~ lessons
Specification detail
Literacy
stories that set a frame or background
stories that accompany or intertwine
stories that introduce
stories that explain
stories that ask a question
stories that entertain
Really Big Numbers by Richard Schwartz
Introducing...
sticky numbers - 1,2
estimating square roots - 1,4
find a and b - 3
examining square roots - 1,4
Developing...
square numbers - 1,2
powers and roots 1 - 1,2,4,5
powers and roots 2 - 1,2,4,5
brahmagupta - 1,5
3 power line - 3,4
5 power line - 3,4
9 power line - 3,4
crossnumber - 1,3,4