Friday, October 29, 2010

Halloween Math

2 X 2 = Boo: A Set of Spooky Multiplication Stories by Loreen Leedy

2 X 2 = Boo: A Set of Spooky Multiplication StoriesThis is a simple, fun book to use during Halloween time for a review of the times table through 5.  It covers the times tables from 0 to 5 in six chapters, cleverly starting from "Chapter 0."  In Chapter 0, a witch named Griselda makes scary creatures disappear, starting with one vampire and ending with 5 ghosts, by multiplying them by zero.  In Chapter 1, a ghost brings in one bag of candy to Dr. Nelson, who then multiplies the one bag by 2,3,4, and 5 to create more bags of candy.  At the end of the chapter, they burst the machine by multiplying one by 99.  In Chapter 2 Griselda puts on "Dr. Spook's Doublevision Spectacles" and sees everything double: a moosehead, 2 boots, 3 witches hats, 4 brooms, and 5 books.  In Chapter 3, a hen and fox need a 3 scarecrows to frighten all the crows eating their corn.  They need 3 pumpkins for heads. Each pumpkin has 2 eyes and 3 teeth.  The scarecrows each need 4 limbs and 5 strings of hair.  In Chapter 4, a big bat shows that he is 4 times bigger than a small bat and needs more to eat.  He takes 1 cookie, 2 rotten apples, 3 slimy worms, 4 stinky fish, and 5 warty toads from the small bat and multiplies them by 4.  In Chapter 5, Mr. Bones and Mrs. Tibia are making a stew.  But the recipe is for one, and they will be serving 5.  So need need 5 times as many of each ingredient: one bouncy eyeball, 2 knobby knuckles, three pointy ears, 4 smelly toes, and 5 scaly tales.  At the end of the book, the 5 times tables are illustrated with pictures from the story.  Quick and easy read.  Ages 6-9.

Friday, October 22, 2010

One Grain Of Rice: A Mathematical Folktale

This wonderful book illustrates both visually and in story the doubling of a number from 1 to one billion.  In the story, a village girl in India outwits a raga who is hoarding the people's rice supply.  She cleverly catches rice that is being spilled from one of the raga's rice baskets in order to turn it in to him for a reward.  She at first modestly replies that he can reward her one grain of rice. When the raja insists on a more substantial reward, she instructs him to give her just one grain of rice that day; but each following day, for thirty days, he is to double the amount of rice he gave her the day before.  The story then illustrates the delivery of rice to the village girl day by day.  The book presents an engaging story, with equally engaging visuals.  The amount of rice presented over the 30 days is illustrated.  On the thirtieth day, the 2 pages of the book open up in additional folds to display together four pages of 256 elephants carrying baskets of rice containing 536,870,912 grains of rice.  This book not only illustrates number and the concept of doubling, it inspires the desire to be knowledgeable about and clever in math. The story, without the mathematical teaching point, stands on its own. Highly recommended.  Ages: K-upper elementary.