Unit 1, Lesson 1 Introducing the MathBoard

MathBoard  The top bar shows one whole. The other bars show this same whole divided into different numbers of equal parts.  The bars are labeled halves, thirds, fourths, and so on.  The bar labeled halves is divided into two equal parts (divided in half), the bar for thirds is divided into three equal parts, and so on.  The number parts increases with each bar, while the size decreases. The whole is the same for all the bars.

Label your fractions  Label the first part of each of the fraction bars on your MathBoard.  What do all the fractions you wrote have in common?  What do we call fractions like these? Unit Fractions

Build a Whole  How can we build 1 whole by adding unit fractions?  For any of the fraction bars, we can build a whole by adding all of its unit fractions.  We can look at the denominator. That is how many of the unit fractions we will need to add to get a whole.  Any fraction with the same numerator and denominator is equal to 1 whole because it represents all of the equal parts in the whole.

Building Other Fractions  Any fraction that is not a unit fraction can be built by adding unit fractions.  is not a unit fraction but we get by adding unit fractions together.  The denominator of the fraction tells you the number of unit fractions in the whole. For example, for, the whole is made up of 5 unit fractions.  The numerator of a fraction tells the number of unit fractions in the fraction. For example, the fraction is made up of 3 unit fractions.

Fraction Problems with the MathBoard  Mr. Ellis is building a sidewalk. Yesterday he built of the sidewalk. Today he built of the sidewalk. What fraction of the sidewalk has he built?  How can we figure out what operation to use?  How do we add the fractions?  We add the numerators and leave the denominators the same.  Use the MathBoard and unit fractions to show why we add the fractions this way.

Fraction Problems on the MathBoard  We had of a pizza. Then we ate of it. How much pizza is left?  What operation do we use?  How can we subtract fractions?  Subtract the numerator and leave the denominator the same  Use your MathBoard and unit fractions to show why we subtract fractions this way.

Find the fraction bar on your math board that looks like this one. 1.Label the first part of the fraction bar with the correct unit fraction. 2.Circle the first 3 parts of the bar. What fraction is represented. 3.Write your answer to number 2 as a sum of unit fractions. 4.Represent the whole as a sum of unit fractions.

Solve the problem below using the fraction bar on your math board. Mark was mowing his yard. He mowed 1/5 of his yard before it started to rain. Later that evening he mowed 2/5 of his yard before it got too dark. How much of his yard did he mow altogether?