Repeating Decimal Period
A division that never terminates still has a rule: the remainders cycle, so the digits after the point repeat in a fixed block. Once a child finds the block, any far-off decimal place is a remainder question rather than a long division -- the 18th or the 20th digit costs the same as the 3rd. This is where 'the division does not end' turns from a dead end into a pattern.
grade 6–7 Number system Look for a PatternIdentify Subproblems
Progression (2)
g7 1. A repeating block gives any decimal place Number system
g7 2. Some decimals repeat forever Number system