Meet the Numbers 11-20: teaching teen numbers with visuals

Just a quick 10-mile stroll with a pole stuck in his side. David Cifaldi was crossing Montana’s Froze-to-Death Plateau when his hiking trip took an unexpected turn. The 32-year-old slipped and impaled himself on his 44-inch steel-tipped trekking pole. The walking aide pierced the flesh beneath the nurse’s left arm – luckily missing any vital organs – and came out his back. After talking over options with his companions, Mr Cifaldi decided to walk himself off the mountain, a six-and-a-half-hour t