4.   Here are two approaches that children used to solve the problem 635 – 482.

 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." 4.1 Does Lexi's reasoning make sense to you? Yes    No 4.2 Does Ariana's reasoning make sense to you?   Yes    No

4.3. Which child (Lexi or Ariana) shows the greater mathematical understanding?

Lexi    Ariana

Why?

 4.4  Describe how Lexi would solve this item:  700 – 573. 4.5 Describe how Ariana would solve this item:  700 – 573.

Click on Submit when you are ready to submit your answers and continue.