Concept:Place value is the idea that each digit in a number has a different value depending on its position. The student's error shows they do not understand that tens and units represent different amounts.
Explanation:The student has 3 tens, which make the number 30. They need to subtract 3 units, which is just 3. So 30 − 3 = 27, not 0.
The student saw the digit '3' in both places and wrongly thought they cancel out. This is a misconception about place value, not a simple mistake.
To correct this, the teacher should first strengthen the idea of place value using hands‑on materials like bundles of sticks or base‑ten blocks.
With concrete objects, children can physically see that 3 tens are 30 and 3 units are only 3. They can then understand why subtracting 3 from 30 leaves 27.
Teaching the standard algorithm or giving more practice will not help until the student grasps place value.
Hands‑on experiences build a strong foundation, so the child learns the meaning behind the numbers.
Answer:D. Strengthening the concept of place value by providing hands‑on experiences