Incredible Numbers ©Touch Press/Profile Books.

Incredible Numbers. Ian Stewart, Theodore Gray, and Phil Ramsden. Touch Press/Profile Books. 2014. iOS, requires 7.0. Version 1.0.1. $9.99.

Gr 7 Up –“Math is Beautiful,” so the introduction to Touch Press’s latest app states–and Incredible Numbers delivers an elegant proof of that claim. Created by professor and pop-science writer Ian Stewart, Wolfram Research co-founder Theodore Gray, and Mathematica expert Phil Ramsden, the app guides users in a visual exploration of mathematical concepts such as pi, polygons, primes, factorials, and infinity as well as applications in cryptography, nature, and music.

The content serves a range of audiences: the text accompanying each section is fairly deep and assumes a basic familiarity with fundamentals of algebra and geometry as well as series, trigonometric functions, and irrational numbers, but selected in-text dictionary functionality (and brief biographies of famous mathematicians) may help. The visual and (70-plus) interactive elements are more welcoming to those who enjoy mathematical exploration but may not yet have the technical vocabulary or exposure to the connections between concepts. The nature and music sections are especially friendly to novices, and a collection of puzzles (answers included) round out the more enticing end of the spectrum for casual users.

Touch Press is known for its deep, immersive productions such as The Elements: A Visual Exploration, and while Numbers is perhaps not as rich an experience, its visuals are appealing and clean and colorful in the iOS 7 style. The interactive elements are occasionally a bit perfunctory, such as requiring a simple swipe or scroll to draw out a pattern, but being able to see data and patterns grow at one’s own pace (or multiple times) will help users grasp concepts. The code-breaking and music sections also allow users to play around, independently investigating the effect of different input.

While the app may not convert the truly math-averse, it will take enthusiasts deeper into the sanctum sanctorum of mathematical beauty.–Gretchen Kolderup, New York Public Library, NY

iF Poems. Allie Esiri and Rachel Kelly, eds. Clickworks Ltd./Chocolate Creative Ltd. 2013. iOS, requires 4.3 or later. Version 1.6.2. $0.99.

PreS Up –A robust collection of more than 260 poems, many of which are narrated. There are a number of access points to the works including: categories, age level, author, title, first line, and sometimes, first word. In all, 102 poets are featured in 12 categories ranging from “Growing Up” and “Short and Sweet” to “War, History & Death” and “About Poetry.” Under each section the poems are sorted by age (0-6, 7-12, or 13+). While the focus is both classic and British (Percy Bysshe Shelley, The Brontës, Robert Lewis Stevenson, William Wordsworth, William Shakespeare), there are surprises (Tim Burton’s “Stick Boy And Match Girl In Love”); a bit of mischief (Mary Howitt’s “The Spider And The Fly”); and plenty of humor (13th century Saadi’s “Observe This Precept Whenever You Can”). A paragraph-length biographical note on the author of the poem precedes each selection, and Natasha Low’s image of a tree trunk filled with words and letters frames it.

The app’s repertoire of readers includes Helena Bonham Carter, Bill Nighy, Tom Hiddleston, and Harry Enfield, all of whom do a superb job evoking the emotional content of the works—and their timelessness. Carter carries many of the humorous selections (A. E. Housman’s “Amelia Mixed the Mustard”), Nighy some of the more serious (Rupert Brooke’s “The Soldier”); all the readings are superbly delivered and will draw listeners deeper into the collection. They will also remind readers of the pleasures of listening to spoken poetry.

Users can choose to record their own readings of the works, and/or save, or share their favorite printed selections via email. In a reverse publishing trend, the poems are now also available in book form, iF: A Treasury of Poems for Almost Every Possibility (ipg Books, 2013).