Why don't start to share the mistakes on this forum ?
The most obvious one is on page 30, where Ohms law is misused. They totally neglect the voltage-drop over the LED, which at this voltage levels is a big error. The calculations are thus wrong, and the conclusions in error.
The text also uses non-standard terminology, such as "the amperage used by the LED", which is at best strange and at worst wrong. All through Project 01 the concepts of voltage, current, power and energy are mixed up. The definitions of current and voltage on page 21 are wrong. The explanation of a resistor on page 25 and how it affects the light from a LED is wrong.
In addition there are lots of smaller things, such as that sensors convert energy into electrical energy, which very few of the sensors we use today actually does. And that a piezo element vibrates when it "receives electricity", which sounds like an explanation from the 18th century.
There are also a number of strange definitions in the Glossary.