Computational error in "Delta-Wye resistor networks" article

Hello there, I found a bug in article "Delta-Wye resistor networks", link below:
https://www.khanacademy.org/science/electrical-engineering/ee-circuit-analysis-topic/ee-resistor-circuits/a/ee-delta-wye-resistor-networks

20 / 12 should be ~= 1.67. Or we can write it like 1.(6) in repeating decimal form.

Later in the article there's a not so correct addition: