## Monday, May 7, 2012

### Who's in Your Family? Math Fact Families

These are family photos. The people in a family may be related by bloodline or adoption or just by living under one roof and sharing common interests.
 Kindlespire Reunion
 Family Travels

There are several definitions of the word family:
noun ( pl. families )
1 a group consisting of parents and children living together in a household.
• a group of people related to one another by blood or marriage: friends and family can provide support.
• the children of a person or couple: she has the sole responsibility for a large family.
• a person or people related to one and so to be treated with a special loyalty or intimacy: I could not turn him away, for he was family.
• a group of people united in criminal activity.
• a group of objects united by a significant shared characteristic.
The final definition applies to more than just people who are related. It applies to objects, numbers, shapes, and much more. Here is a photos of the Excel Math family of employees (taken a few years ago):

There are families in mathematics, too. We call these fact families.

In Excel Math we teach students to recognize addition and subtraction fact families. Help your students learn to recognize fact families. Begin by listing the following number sentences on the board. These are all part of a "fact family" (but don't tell your students yet):
2 + 3 = 5
3 + 2 = 5
5 – 2 = 3
5 – 3 = 2

Ask your students if they can see how all of these number sentences are related. (They are all considered part of the same "fact family.") By recognizing the relationships in the addition and subtraction fact families, a student can know four different basic facts by memorizing just one fact.

Have your class look at this Student Lesson Sheet from Excel Math Grade 1 Lesson 71:
You can print this worksheet and use it with your class. Explain that if they know 2 + 1 = 3 they also know:
1 + 2 = 3
2 = 1
3 – 1 = 2

These number sentences are all part of the same fact family. Poing out that a fact family is a set of related numbers. Talk through the fact families on this worksheet where the answers are given. Have a student describe how the problems in the first box are related. (They include problems using the numbers 1, 2 and 3.) Do the same with the next box. Let your students fill in the missing problems in the next two boxes. Have a student describe each of these fact families.

Give the children a chance to complete the Basic Fact Practice. Go over any of the problems your students have difficulty solving.

If you have time (or for students who finish early), give each student a blank piece of paper and let him continue to create fact families (one or two additional equations) using the problems given for Basic Fact Practice.

If you have children who would like to share one interesting thing about their own families, let them do so. Begin by sharing about your own family.

Since Excel Math uses a unique spiraling strategy, you will need to teach multiple lessons sequentially within each grade level in order to get the concepts into your students' long-term memory. A student's learning of new concepts takes place during Excel Math Lesson Plans and Activities. The concepts are refreshed through Guided Practice, Homework, Create A Problem and Tests.

Visit the Excel Math web store to order these Student Lesson Sheets (155 lesson sheets plus tests) and a Teacher Edition set of 155 Lessons with brainteasers, teaching suggestions, the answer key, and reproducible manipulatives for each grade  level. Excel Math is available for Kindergarten through Grade 6.