Study Guide - Chapter 2 - Lessons 1-4
Chapter 2:
Lesson 1: Students should be able to group tens or doubles to add more than two addends.
Example: grouping tens: 4+5+1+5 = _____
5+5=10
10+1+4=15
Example: grouping doubles: 8+4+0+4= _____
4+4=8
8+8+0=16
Lesson 2: Students should be able to find the missing addend.
Example: ?+4+2= 12
4+2=6
?+6 = 12
12-6=?
12-6 = 6
The missing addend is 6
Students should review the worksheet “Balancing Equations”.
Lesson 3: Students should be able to add 2 and 3-digit numbers without regrouping.
Example: 235 + 111 = add ones first, then the tens, then the hundreds, from right to left. - answer is 346
hundreds tens ones
2 3 5
1 1 1
Lesson 4: Students should be able to estimate sums by rounding to the nearest ten or hundred. Example:
1) 24+13+47=?
20+10+50 = 80 (estimation by rounding to the nearest 10)
2) 917+245=?
900+200 = 1100 ( estimation by rounding to the nearest 100)