La historia de los sistemas numéricos: Valor posicional (The History of Number Systems: Place Value)

Introduces numbers one through nine and provides the reader with the opportunity of counting such things as animals, flowers, balloons, and umbrellas.

Presenta un tratamiento claro, amplio y riguroso de los contenidos. Permite la atención a la diversidad del alumnado manteniendo como objetivo fundamental su preparación para la Universidad.

Ofrece una explicación de las soluciones y mezclas y en qué se diferencian, así como ejemplos de mezclas y soluciones.

Lara Finch lives a lie. Everyone thinks she is happily married to the faithful Sam. She is actually super bored and misses working. Behind Sam's back, she takes a job in London. Twice a week she takes the sleeper train, where she meets Ellen and Guy. One Friday, Lara disappears from the train without a trace. Her friend Iris does not believe the official story she is told about the disappearance and decides to start her own investigation. Iris cannot believe what she finds out.