Choosing Fraction Operations in Stories

Create the complete application lesson for Section 7.8-D. Use Arin only. This video applies previously learned methods; do not reteach every procedural step from the beginning. 1. INTRODUCE four problem cards: Juice, Lace, Distance, and Which Is More? 2. JUICE: 2/3 L + 3/4 L. Ask which operation is needed. Show 8/12 L + 9/12 L = 17/12 L = 1 5/12 L. Check that the total exceeds one litre and interpret the unit as litres. 3. LACE: 2/5 m + 3/4 m. Show 8/20 m + 15/20 m = 23/20 m = 1 3/20 m. Compare the result with the required 1 m and show that 3/20 m is extra. 4. DISTANCE: the journey is 7/10 km and 1/2 km has already been travelled. Convert 1/2 km to 5/10 km; calculate 7/10 − 5/10 = 2/10 = 1/5 km remaining. 5. COMPARE: compare 1/2 km and 5/8 km. Convert 1/2 = 4/8; conclude that 5/8 km is greater. 6. SUMMARISE: understand the story before choosing addition, subtraction or comparison. Explain the meaning of the final answer and retain the correct units. 7. MISCONCEPTION CHECK: display 2/3 + 3/4 and the incorrect claim 5/7. Ask what is wrong, then explain that denominators describe the size of the fractional unit and must not simply be added. 8. FINAL CHALLENGE: 3/4 L + 2/5 L. Ask learners to identify the operation, find a common denominator and check whether their result is reasonable. Leave the problem unsolved for practice. Use clear story visuals for litres, metres and kilometres. Keep the focus on selecting an operation, interpreting units and checking reasonableness. Do not repeat a full procedural lecture already taught in Videos 7.8-A to 7.8-C.