Criptología digital (Digital Cryptology)

For many years, people believed there were nine planets that orbited the sun. Now we say there are eight. What happened to the ninth planet, Pluto? What are the different planets like? What exactly makes a planet a planet? These are the many intriguing questions answered with this high-interest book, crafted to be accessible for readers of all levels. Young astronomers will be especially fascinated by the stunning photographs and the "Make the Grade" fact boxes.

"Dino" Don Lessem brings readers face-to-face with various dinosaur species, detailing their habitats, way of life and how they became extinct. An acclaimed dinosaur expert, Don Lessem has written more than 30 children's books, writes a popular dinosaur column in Highlights magazine, and was an adviser for Jurassic Park. Take a trip through dinosaur time to meet these fast dinosaurs face-to-face: The Gallimimus could outrun a sandstorm! The Struthiomimus may have been the fastest dinosaur. It could run up to 60 miles per hour! The Liaraptor ran until it took off into the air! These may have...

Libro de gran formato con rimas y textos sencillos, colores vivos y texturas variadas que invitan a los más pequeños a experimentar a través del tacto y la vista. ¿Quién se esconde tras las solapas?

Students will develop their geometry skills as they study the geometric shapes of modern art and read about the innovative artists who turned the art world upside down. This Spanish book seamlessly integrates the teaching of math and reading, and uses real-world examples to teach geometry concepts. Text features include a glossary, an index, captions, and a table of contents to increase students' vocabulary and reading comprehension skills as they interact with the text. The rigorous practice problems, math charts and diagrams, and sidebars provide many opportunities for students to practice...