Question

Constructed Response 1: A student thinks that the sum of 4.3 and 8.4 is 12.7 because 4 + 8 = 12 and 3 + 4 = 7. The student then adds 3.6 and 2.7 and gets 5.13 because 3 + 2 = 5 and 6 + 7 = 13. Identify the mistake in the student’s procedure and explain why this procedure won’t always work. *

Answer 1

6 + 7 = 13 (so more than 10)

So you must add that 1 to te result of 3+2

1+2+3= 6

Final result : 6.3