[{"id": 1, "type": "multiple_choice", "skill": "fractions", "options": ["3/4", "1/2", "2/4", "3/8"], "question": "What is 1/4 + 2/4?", "difficulty": "medium", "explanation": "Same denominator: add numerators. (1+2)/4=3/4.", "needs_review": false, "correct_answer": "3/4"}, {"id": 2, "type": "short_answer", "skill": "fractions", "question": "Simplify: 6/8", "difficulty": "medium", "explanation": "Divide numerator and denominator by GCF (2): 6÷2/8÷2=3/4.", "needs_review": false, "correct_answer": "3/4"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 20", "difficulty": "medium", "explanation": "Multiply: 16×20=320", "needs_review": false, "correct_answer": "320"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 17", "difficulty": "medium", "explanation": "Multiply: 10×17=170", "needs_review": false, "correct_answer": "170"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 18", "difficulty": "medium", "explanation": "Multiply: 19×18=342", "needs_review": false, "correct_answer": "342"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 19", "difficulty": "medium", "explanation": "Multiply: 19×19=361", "needs_review": false, "correct_answer": "361"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 8", "difficulty": "medium", "explanation": "Multiply: 4×8=32", "needs_review": false, "correct_answer": "32"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 19", "difficulty": "medium", "explanation": "Multiply: 7×19=133", "needs_review": false, "correct_answer": "133"}]