Adding and Subtracting Fractions Warm up What is

Adding and Subtracting Fractions

Warm up What is the lowest common multiple of: Find a the missing numbers 2 = 6 3 and 4 12 5 15 5 and 6 30 4 and 6 12 3 15 = 8 40 3 and 8 24 5 and 10 10 25 5 = 6 30

Adding and Subtracting Fractions Two rulers add three rulers is: 5 rulers Four pens add five pens is: 9 pens Two pens add Five rulers is: 7 Pieces of equipment We can’t so this until we have a name that describes both groups When we add fractions we need them to have the same name

Adding and Subtracting Fractions 2 3 = 5 + 7 7 7 2 4 = 6 + 9 9 9 1 3 = 4 + 11 11 11

Adding and Subtracting Fractions 2 3 = 5 + 7 7 7 2 4 = 6 + 9 9 9 5 3 = 2 11 11 11

Adding and Subtracting Fractions We need to make sure the denominator of both fractions is the same before we add or subtract 2 3 = + 5 10 4 3 7 + = 10 10 10 We need a number in the 5 and 10 times table to use as our bottom number 10?

Adding and Subtracting Fractions We need to make sure the denominator of both fractions is the same before we add or subtract 1 5 = + 3 12 4 5 9 + = 12 12 12 We need a number in the 3 and 12 times table to use as our bottom number 12?

Adding and Subtracting Fractions We need to make sure the denominator of both fractions is the same before we add or subtract 2 3 = + 5 6 12 15 27 + = 30 30 30 We need a number in the 5 and 6 times table to use as our bottom number 30?

Adding and Subtracting Fractions We need to make sure the denominator of both fractions is the same before we add or subtract 7 2 = 8 3 21 16 5 = 24 24 24 We need a number in the 8 and 3 times table to use as our bottom number 24?

a) b) c) d) e) 7/8 8/12 7/9 7/10 2/3 a) b) c) d) e) 11/12 7/10 8/15 16/12 or 1 ¼ 11/24 a) b) c) d) e) 1 7/12 1 5/56 29/30 29/52 1 1/10 a) b) c) d) e) 5/8 5/12 1/3 2/5 1/2 a) b) c) d) e) 7/20 8/21 23/36 9/22 71/126 Adding and Subtracting Fractions Click for answers