Size up That Spinosaurus – and Help Write Our Next Book!

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

Size up That Spinosaurus – and Help Write Our Next Book!

March 3, 2016

First, thank you all for sending us such awesome questions to answer. And guess what? We’re going to make a whole book of them, and YOU can help write it! Visit our website to send in your wacky question. We’ll answer them all at least on the app and website, and better yet, a lucky bunch will make it into the book. Either way, you’ll get to see your name in print!

For today, we got a great question from our friend and fan David K.: how much does a spinosaurus weigh? (and with an equally great picture). This is tricky — after all, we don’t have live dinosaurs running around today who could step on a bathroom scale and weigh themselves. But scientists have tried to guess. The spinosaurus gets its name from the huge 5-foot spines along its back. But we have only bones to help us guess the weight; we don’t know exactly how much skin, fat and muscle they had. So depending on how much “stuff” held those spines onto the body, the animal could have weighed anywhere from 8 to 23 tons. Of course, these dinos were about 50 feet long…so they probably wouldn’t fit on that little bathroom scale anyway.

Wee ones: Who’s taller, you or a 5-foot-tall spike on a spinosaurus? Find out your height in feet!

Little kids: How much taller than you is that 5-foot spine — or how much taller are you?  Bonus: If you have a 10-foot measuring tape, how many times would you have to stretch it to measure that 50-foot body?

Big kids: A 23-ton spinosaurus would weigh almost 3 times an 8-ton one, if that turned out to be right. How much would YOU weigh if you turned out to weigh 3 times as much?  Bonus: How much more does a 23-ton stegosaurus weigh than a 6-ton elephant, in pounds? (Reminder if needed: A ton has 2,000 pounds.)

The sky’s the limit: If you have 3 spinosaurus of different sizes, and the first 2 together weigh 11 tons, the 2nd and 3rd together weigh 22 tons, and the 1st and 3rd together weigh 15 tons, how much does each one weigh?




Wee ones: Different for everyone…see if your height is more or less than 5 feet.

Little kids: Different for everyone again…subtract your height from 5, or subtract 5 from your height.  Bonus: 5 times.

Big kids: Different again…multiply your weight by 3. You can also add it to itself, then add it on 1 more time.  Bonus: 34,000 pounds, since it weighs 17 tons more.

The sky’s the limit: 2, 9 and 13 tons. If the 1st and 2nd weigh 11 and the 1st and 3rd weigh 15, then swapping out the 2nd dino for the 3rd increased the total by 4 tons. So the 3rd weighs 4 tons more than the 2nd dino. Together those 2 weigh 22 tons, so if the 3rd were as small as the 2nd, they’d weigh just 18 tons. That means the 2nd dino weighs 9 tons, and you can figure out the other 2 from there.

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About the Author

Laura Overdeck

Laura Overdeck

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking while still in diapers, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.

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