You can do both with this book—no writin’ required! It’s The Little Book of Mathematical Principles, Theories, & Things, which is a title we love, despite the Oxford comma. By math whiz, author and professor Robert Solomon, the paperback volume has (224) pages. Measures an easily totable 5-1/2" X 7", letting you peruse a lesson on Binary Numbers, The Golden Ratio, Logarithms, Chaos Theory, Russell’s Paradox, Fermat’s Last Theorem, or about 115 others, each (1) to (2) pages long, whenever you have a spare minute to learn.

If you're devoted to explosions, and who isn't, you'll love the new expanded 2nd edition of William Gurstelle's Backyard Ballistics, now 25% longer, with 25% more ka-boomery. Still the go-to reference work for building rockets, cannons (carbide and potato), flingers, fire kites, electromagnetic pipe guns, tennis ball mortars, cleaner-bag balloons, ballistic pendula and petards. You simply can't have more fun with common household materials. The soft-cover, 210pp compendium includes detailed and illustrated instructions, parts lists and sensible ways not to be hoist on your own petard. Be careful out there.

When we were kids, the only toy we had was a cardboard box. Walked uphill to and from school, too-both ways. And in the rain. Imagine what we could have done if we’d have had Cardboard Box Engineering, the (175)-page book full of photos, illustrations, educational facts and instructions on how to turn household items into games, airplanes, robots, gears, solar cookers and more. Kids can design, tinker and build their own outside-the-box creations, Get it? Outside the box? From best-selling author Jonathan Adolph. Made in USA.

Learn atomic weights while winning money from your classmates. Here’s a double deck of (104) cards plus (4) jokers all stored in a stylish box because no one wants to lose their gold, krypton or rubidium. In addition to the standard playing card values, the decks cover the periodic table of elements. Each card includes one element’s atomic number, symbol, series, melting and boiling points, period/group, uses, est. atomic weight, standard state, and the element’s name in English. Includes instructions for (2) educational games if you aren’t in the mood for canasta or two games of hearts. Up to date 6th Edition for all your fraction of a second elements.

Start them out right with this (profusely) hand-illustrated, 96-page book: The Story of Inventions. Includes toasters, toilets, television, computers, cars, chocolate bars, dishwashers, pianos, flying machines, bicycles and blue jeans among many others. Includes a timeline, glossary and index. No age recommendations, but we like it for pretty much anyone.

50 Science Things to Make and Do is just that, a passel of experiments, all illustratively explained in two facing pages of this big 104-page flip book, and all easily done with common household items. Includes wind and water power, bugs, crystals, paper planes, rubber-band guitars, balances, gloop, optics and a ton of other fun, informative stuff. Officially classified as "cool" by several of our geekiest staffers.

Time was, the Scouts taught tots how to tie a few knots, but that was before John Sherry (knot-instructor par excellence and a member of the International Guild of Knot Tyers) came along with Knot It! a (126)-page hardcover book with illustrated instructions for tying (100) different knots. Our faves are the Schwabisch Hitch and the Slippery Night Loop. Includes a couple of 15” hanks of practice paracord and waterproof cards with (20) knot instructions. This could be your new hobby.

Our grandmother used to tell us that all the time, and we might have learned something while we were out there if she’d given us The Kid’s Guide to Exploring Nature, this 120-page paperback from the Brooklyn Botanic Garden. Chock full of information, photos and illustrations for exploring nature in both the city (includes pigeon info!) and the countryside, and in all four seasons. They might stay out of your hair until supper.

If you make cool stuff, people will pass it on to your children’s children’s children and you won’t spend eternity as just an old picture on a lost thumb drive. We suggest: Making Poor Man’s Guitars, a 176-page paperback with detailed instructions for building string instruments out of cigar boxes, frying pans, tin cans, mailboxes and washtubs, with a beer-can microphone thrown in.

Cheaper -- a whole lot cheaper -- than hiring a guide, plus these fit in your pocket (which is only true of the tiniest human guides). These hunting and fishing helpers are written and illustrated by professionals and are dense with information and step-by-step, full-color instructions for deer and duck hunters and fisherpersons. They're printed on heavy laminated 8-1/2" x 11" stock folded to a pocket-sized 4-1/4" x 5-1/2". The series includes how to cast for and trigger bass; and how to work with minnow rigs -- which is always a plus. Original retail price of each was $4.95.