[{"id": 1, "type": "multiple_choice", "skill": "fractions", "options": ["2/4", "3/8", "3/4", "1/2"], "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 × 9", "difficulty": "medium", "explanation": "Multiply: 16×9=144", "needs_review": false, "correct_answer": "144"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 14", "difficulty": "medium", "explanation": "Multiply: 7×14=98", "needs_review": false, "correct_answer": "98"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 19", "difficulty": "medium", "explanation": "Multiply: 17×19=323", "needs_review": false, "correct_answer": "323"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 13", "difficulty": "medium", "explanation": "Multiply: 8×13=104", "needs_review": false, "correct_answer": "104"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 11", "difficulty": "medium", "explanation": "Multiply: 10×11=110", "needs_review": false, "correct_answer": "110"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 2", "difficulty": "medium", "explanation": "Multiply: 12×2=24", "needs_review": false, "correct_answer": "24"}]