Record an estimate that is:

1. Find the value of . Explain or show your reasoning.

2. Elena and Andre try to find the value of . Who do you agree with? Explain or show your reasoning.

   

   Elena, Add. The two numbers are right aligned. 6 hundred 21 point 4 5, plus, 72 point 3, equals, 6 hundred 28 point 6 8. Written underneath, my answer makes sense because it is more than 6 hundred 21. Andre, Add. The two numbers are right aligned. 6 hundred 21 point 4, 5, plus, 72 point 3, 0, equals, 6 hundred 93 point 7, 5. Written underneath, my answer makes sense because 6 hundred 20 plus 70 equals 6 hundred 90 and then I still have to add a little bit more than 3 to 6 hundred 90. 

Find the value of each expression. Explain or show your reasoning.