U

unit of measure

A fixed quantity used to measure. For example, centimeter, foot, kilogram, and quart are units of measure.

pages 349, 401

unit whole

The shape or piece that is equal to 1.

pages 250–256, 262–263, 264

unlikely event

Something that can happen but probably will not.

page 11

using-doubles strategy

Strategies for addition and subtraction that use known doubles. For example, one can find 7 + 8 by thinking 7 + 8 = 7 + 7 + 1 = 14 + 1 = 15. Knowing 7 + 7 = 14 can be helpful in finding 14 − 7 = 7 and 14 − 8 = 6.

pages 199, 238

using-ten strategy

1. A strategy for addition that uses the number 10. For example, one can find 9 + 5 by thinking 10 + 5 = 15 so 9 + 5 is one less or 14.

2. A strategy for subtraction that uses facts that involve subtracting 10. For example, one can use 17 − 10 = 7 to learn the “close fact” 17 − 9 = 8.

pages 126–127