C2b
Practice - Adding & Subtracting Fractions
TRY TO ANSWER IN TWO AND A HALF MINUTES.
QUESTIONS
QUESTIONS
1. Add 7/8 and 13/16.
2. Subtract 1-3/8 from 5-1/4.
3. What is 1-4/5 - 7/16 + 5/8 ?
4. What is 7/16 - 2-2/3?
ANSWERS
1. The least common denominator of 8 and 16 is 16. 7/8 = 14/16. 14/16 + 13/16 = 27/16.
2. The least common denominator of 8 and 4 is 8. 1-3/8 = 11/8. 5-1/4 = 21/4 = 42/8. 42/8 - 11/8 = 31/8.
3. The least common denominator of 5 and 16 and 8 is 80. 1-4/5 = 9/5, x 16/16 = 144/80. 7/16 x 5/5 = 35/80. 5/8 x 10/10 = 50/80. 144/80 - 35/80 + 50/80 = 159/80.
4. The least common denominator of 16 and 3 is 48. 7/16 x 3/3 = 21/48. 2-2/3 = 8/3 x 16/16 = 128/48. 21/48 -128/48 = -107/48.
CALCULATOR STEPS
1. Press on and clear. Press n/d. Key in 7. Press down. Key in 8. Press right. Press + . Press n/d. Key in 13. Press down. Key in 16. Press right. Press enter. The screen should show "27/16".
2. Press on and clear. Press 2nd and n/d. Key in 5. Press right. Key in 1. Press down. Key in 4. Press right. Press - . Press 2nd and n/d. Key in 1. Press right. Key in 3. Press down. Key in 8. Press right. Press enter. The screen should show "31/8".
3. Press on and clear. Press 2nd and n/d. Key in 1. Press right. Key in 4. Press down. Key in 5. Press right. Press - . Press n/d. Key in 7. Press down. Key in 16. Press right. Press + . Press n/d. Key in 5. Press down. Key in 8. Press right. Press enter. The screen should show "159/80".
4. Press on and clear. Press n/d. Key in 7. Press down. Key in 16. Press right. Press - . Press 2nd and n/d. Key in 2. Press right. Key in 2. Press down. Key in 3. Press right. Press enter. The screen should show "-107/48".