Fractions and Ratios Made Easy
Grade 5 Mathematics Understanding Parts and Wholes 45-minute lesson
What Are Fractions?
A fraction shows parts of a whole The top number is the numerator (parts we have) The bottom number is the denominator (total parts) Example: 3/4 means 3 out of 4 equal parts
Fraction Examples in Daily Life
{"left":"Half a sandwich (1/2)\nQuarter of an hour (1/4)\nThree-fourths of a chocolate bar (3/4)","right":"Two-thirds of a glass of milk (2/3)\nOne slice of an 8-piece pizza (1/8)\nFive minutes out of ten (5/10)"}
Adding Fractions with Same Denominators
When denominators are the same, just add the numerators Keep the denominator the same Example: 2/5 + 1/5 = 3/5 Think: 2 pieces + 1 piece = 3 pieces out of 5 total
Practice Time: Adding Fractions
Solve these problems: 1/4 + 2/4 = ? 3/8 + 1/8 = ? 2/6 + 3/6 = ? Work with a partner and use drawings to help!
Think About It
If you eat 2/8 of a pizza for lunch and 3/8 for dinner, how much pizza did you eat in total? Draw a picture to show your thinking!
What Are Ratios?
A ratio compares two or more quantities It shows how much of one thing compared to another Can be written as 3:2 or 3 to 2 Example: 3 red apples to 2 green apples
Ratios in Our Classroom
{"left":"Boys to girls\nWindows to doors\nDesks to chairs","right":"Books to pencils\nTeachers to students\nComputers to tablets"}
Ratio Detective Challenge
Look at this picture of colored blocks Count the blue blocks and red blocks Write the ratio of blue to red Write it two different ways: with ':' and with 'to'
Remember
Mathematics is not about numbers, equations, computations, or algorithms: it is about understanding. - William Paul Thurston