Ably demonstrates finding thoughtful solutions for common problems. Cole’s educational story brims with math problems that characters solve (readers can also find the solutions). The bright, young cast is likable despite Stephanie and Justin’s squabble (both sides have reason to be hurt). And it’s a delight when Catherine and Jordan work hard to fix real-world problems…A helpful appendix clarifies some of the more complex mathematics, like the order of operations. ~ Kirkus Reviews

A Knotty Problem features all of the scintillating brain-twisters that one associates with the series, while its more personal stakes have a grounding effect. The Kids’ abilities may be extraordinary, but the challenges they face are much the same as those that average fifth-graders face, whether over maintaining the bonds of friendship in difficult times, or learning the value of teamwork on a soccer field or during a high-pressure quiz.
As always, the book supplies plenty of useful math knowledge, ranging from the concept of the Gordian Knot, which plays a key role in the resolution of Justin’s dilemma, to a biography of George Polya, the “father of problem-solving.”
And its characterizations are deft, so that the Kids’ squabbles and efforts to do what’s right are heartwarming.
Charming illustrations complement the book’s friendly tone.
Capped off with a tense final math showdown (the full solutions for which are included in the book’s informative appendix), A Knotty Problem continues the Math Kids series’ streak of providing entertainment and enlightenment. ~ Forward Reviews