These simple math secrets and tricks will forever change how you look at the world of numbers.Secrets of Mental Math will have you thinking like a math genius in no time. Get ready to amaze your friends—and yourself—with incredible calculations you never thought you could master, as renowned “mathemagician” Arthur Benjamin shares his techniques for lightning-quick calculations and amazing number tricks. This book will teach you to do math in your head fast...

A New York Times bestselling mathematician reveals how math can take your game playing and puzzle solving to the next level.Imagine entering a bingo parlor where one thousand cards are in play. “I’ll bet that the winning card is horizontal instead of vertical,” a man says. Should you take the bet? Or suppose you’ve reached Final Jeopardy! with $7,000 to your opponents’ $8,000 and $4,000. What should you wager?Or im...

The world's greatest mental mathematical magician takes us on a spellbinding journey through the wonders of numbers (and more)"Arthur Benjamin . . . joyfully shows you how to make nature's numbers dance." -- Bill Nye (the science guy)The Magic of Math is the math book you wish you had in school. Using a delightful assortment of examples-from ice-cream scoops and poker hands to measuring mountains and making magic squares-this book revels in key mat...

The history, formulas, and most famous puzzles of graph theoryGraph theory goes back several centuries and revolves around the study of graphs—mathematical structures showing relations between objects. With applications in biology, computer science, transportation science, and other areas, graph theory encompasses some of the most beautiful formulas in mathematics—and some of its most famous problems. The Fascinating World of Graph Theory explores the ques...

In a noisy world hungry for peace and purpose, this devotional calls you to rediscover the quiet, powerful voice of the Holy Spirit. Over forty days, you'll journey from surface religion into spiritual depth-learning to recognize God's whispers, rest in His love, and walk boldly in His leading.Each day offers a sacred rhythm of prayer, reflection, and fasting that turns your daily moments into holy encounters. The Spirit meets you where you are-transforming commutes into communion,...

As I look back now on the sensational events of the past months since the great European War began, it seems to me as if there had never been a period in Craig Kennedy's life more replete with thrilling adventures than this. In fact, scarcely had one mysterious event been straightened out from the tangled skein, when another, even more baffling, crowded on its very heels. As was to have been expected with us in America, not all of these remarkable experiences grew either directly or indire...

THE PERUVIAN DAGGER "There's something weird and mysterious about the robbery, Kennedy. They took the very thing I treasure most of all, an ancient Peruvian dagger." Professor Allan Norton was very much excited as he dropped into Craig's laboratory early that forenoon. Norton, I may say, was one of the younger members of the faculty, like Kennedy. Already, however, he had made for himself a place as one of the foremost of South American explorers and archaeologists. "How they got into the ...

I am not by nature a spy, Professor Kennedy, but—well, sometimes one is forced into something like that." Maude Euston, who had sought out Craig in his laboratory, was a striking girl, not merely because she was pretty or because her gown was modish. Perhaps it was her sincerity and artlessness that made her attractive. She was the daughter of Barry Euston, president of the Continental Express Company, and one could readily see why, aside from the position her father held, she should be am...

THE CLUTCHING HAND "Jameson, here's a story I wish you'd follow up," remarked the managing editor of the Star to me one evening after I had turned in an assignment of the late afternoon. He handed me a clipping from the evening edition of the Star and I quickly ran my eye over the headline: "THE CLUTCHING HAND" WINS AGAIN NEW YORK'S MYSTERIOUS MASTER CRIMINAL PERFECTS another COUP CITY POLICE COMPLETELY BAFFLED "Here's this murder of Fletcher, the retired banker and trustee of the Universi...

Until I receive those materials from Doctor Leslie to make the poison tests, considered Kennedy, as we walked slowly the few blocks to the laboratory, "I can't see that there is much I can do but wait." In his laboratory, he paused before his well-stocked shelves with their miscellaneous collection of books on almost every conceivable subject. Absently he selected a volume. I could see that it was one of the latest translated treatises on this new psychology from the pen of the eminent sci...

A CAMERA CRIME "Camera!" Kennedy and I had been hastily summoned from his laboratory in the city by District-Attorney Mackay, and now stood in the luxurious, ornate library in the country home of Emery Phelps, the banker, at Tarrytown. "Camera!—you know the call when the director is ready to shoot a scene of a picture?—well—at the moment it was given and the first and second camera men began to grind—she crumpled—sank to the floor—unconscious!" Hot and excited, Mackay endeavored to reenact...

I'm so worried over Gloria, Professor Kennedy, that I hardly know what I'm doing." Mrs. Bradford Brackett was one of those stunning women of baffling age of whom there seem to be so many nowadays. One would scarcely have believed that she could be old enough to have a daughter who would worry her very much. Her voice trembled and almost broke as she proceeded with her story, and, looking closer, I saw that, at least now, her face showed marks of anxiety that told on her more than would hav...