[{"id": 1, "type": "multiple_choice", "skill": "fractions", "options": ["2/4", "1/2", "3/4", "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: 8 × 19", "difficulty": "medium", "explanation": "Multiply: 8×19=152", "needs_review": false, "correct_answer": "152"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 20", "difficulty": "medium", "explanation": "Multiply: 14×20=280", "needs_review": false, "correct_answer": "280"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 16", "difficulty": "medium", "explanation": "Multiply: 4×16=64", "needs_review": false, "correct_answer": "64"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 8", "difficulty": "medium", "explanation": "Multiply: 13×8=104", "needs_review": false, "correct_answer": "104"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 15", "difficulty": "medium", "explanation": "Multiply: 6×15=90", "needs_review": false, "correct_answer": "90"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 2", "difficulty": "medium", "explanation": "Multiply: 6×2=12", "needs_review": false, "correct_answer": "12"}]