Question 4 (continued)

Here are those two approaches again so that you can refer to them to finish this section.

 Lexi                                  5613 5                –  4 8 2                    1 5 3     Lexi says, "First I subtracted 2 from 5 and got 3. Then I couldn't subtract 8 from 3, so I borrowed. I crossed out the 6, wrote a 5, then put a 1 next to the 3. Now it's 13 minus 8 is 5. And then 5 minus 4 is 1, so my answer is 153." Ariana   635 –  400  =  235 235 –    30 =   205 205 –    50 =   155 155 –      2 =   153            482         Ariana says, "First I subtracted 400 and got 235. Then I subtracted 30 and got 205, and I subtracted 50 more and got 155. I needed to subtract 2 more and ended up with 153."

For the remaining questions, assume that students have been exposed to both approaches.

 4.6  Of 10 students, how many do you think would choose Lexi's approach? of 10 students would choose Lexi's approach. 4.7  If 10 students used Lexi's approach, how many do you think would be successful in solving the problem 700 – 573?   of 10 students would be successful.   Explain your thinking. 4.8  Of 10 students, how many do you think would choose Ariana's approach? of 10 students would choose Ariana's approach. 4.9  If 10 students used Ariana's approach, how many do you think would be successful in solving the problem 700 – 573?   of 10 students would be successful. Explain your thinking.

4.10 If you were the teacher, which approach would you prefer that your students use?