Belles on Their Toes , the 1950 sequel to Cheaper by the Dozen, tells how the Gilbreth family was raised by Lillian Moller Gilbreth after the death of Mr. Gilbreth. Despite the family's difficulties as they attempt to balance their budget enough to stay together while Mrs. Gilbreth attempts to make it in the male field of motion study, it still has its predecessor's trademark humor.
This book contains the following tropes:
- Amazingly Embarrassing Parents: Mother unintentionally creates problems for her children at school by telling stories of how the family uses motion study at home, such as the bath charts.
- Animal Lover: Tom the handyman has a large number of stray animals that he feeds and doses with quinine when they show up looking sick. One chapter has him showing off to Mother's class by demonstrating that he trained the latest cat, Fourteen, to jump up on the icebox for her milk so that the children don't step on her.
- Anything but That!: Tom, the handyman, generally gathers the children in the kitchen for what he calls his "club" (which includes refreshments and storytelling). When he attempts to threaten Ernestine with exclusion from it for scratching her chicken pox, she gasps "in mock terror", "Not that! Anything but that!"Tom made no reply. But it was clear that the Princess, as Tom called her, was out of the Club for a thousand years and four days.
- Broke Episode: A running theme is how the children scheme to save money now that Mother's the only one working. Memorably, they decide to stretch the food budget by starting a vegetable garden, then going around to all the local stables with a wheelbarrow collecting horse manure to save $12 ($200 in 2022 money) on fertilizer. Martha in particular becomes obsessed with pinching pennies.
- Cerebus Syndrome: We find out in a footnote in the first chapter of Belles on Their Toes that Mary, the second child, died of diphtheria in 1912. This was apparently too depressing to even mention in Cheaper by the Dozen, so in that book, Mary is born in the chapter "Have You Seen the Latest Model?" and just kind of...isn't mentioned in the rest of the book. They even talk about having twelve children in their car at once...even though Mary died long before the last baby was born, so that couldn't have been the twelve Gilbreth children.
- Disguised in Drag: While some of the others are trying to get rid of Ernestine's fiance, who they think isn't good enough for her, Bill disguises himself as a girl and walks into the bathroom while said fiance is bathing.
- Tone Shift: Cheaper by the Dozen is a collection of semi-independent chapters that jumps around in time a lot. Belles on Their Toes is told in straightforward chronological order.
- Lethal Chef: While Tom alleges he can cook, he really can't. One leg of lamb he roasts with tomatoes is described as looking like an animal leg needing dressing for a wound. It is so bad that when one of the boys comes down with chicken pox, Anne wonders initially if it was the roast lamb he ate.
- Obligatory Joke: During one chapter where the Gilbreth boys are shopping for clothes en masse and the salesman asks them what they "want in a shoe", one of the boys tells the others that they had better not say "a foot" to avoid bothering the salesman any more than they are.
- Old-Timey Bathing Suit: A carry-over from the first book. When the family goes on holiday, Martha packs everyone's suit but her own. Undeterred, she says she will wear Mother's old two-piece suit. At the time, a "two-piece" swimsuit consisted of a form-fitting undergarment that fell below the knee, covered up by a voluminous belted sailor-style dress. Her sisters tell her she's going to look ridiculous...until the curvy Martha shows up on the beach wearing only the undergarment with the legs rolled up as high as she can get them, resulting in an outfit considerably more revealing than her sisters'.
- One-Steve Limit: Averted. Anne's fiance and eventual husband is called Bob, requiring the family to call him "Doctor Bob" to avoid confusing him with their Bob.
- Outliving One's Offspring: While not mentioned in the original book, here it is revealed that Mother and Dad outlived their second child Mary, who died of diphtheria in 1912.
- Present Peeking: One Christmas morning before dawn, Martha comes downstairs to find Mother poking and shaking the presents to find out what they are. Mother confesses that she and Dad always used to come down for "a preview."
- Quitting to Get Married: During one of the later chapters, Anne finds a doctor named Bob to whom she will eventually be married. She tells Mother that she really doesn't care about finishing college and would like to get married "right away." Mother insists that she finish her degree first, but she is pleased with the fact that Anne feels so strongly about the match.
