Why did we need a common denominator to add and subtract fractions?
How would we add 2.56 + 3.18?
How does this relate to finding a common denominator for adding fractions?
Ex 1: Add. (It may be helpful to use graph paper to help line up digits.)
a.
4.56 + 2.9
b.
102.8 + 3
c.
0.564 + 0.8 + 3.1
d.
16.2 + 23.5 + 3.8
Should the rules be the same or different for subtracting decimals?
Ex 2: Subtract. (It may be helpful to use graph paper again.)
a.
3.785 ­ 0.32
b.
25.1 ­ 15.06
c.
9 ­ 2.3
d.
100 ­ 31.93
Compensation is easier than borrowing. Work your way up. 100 ­ 31.93
Try these:
a.
40 ­ 29.1
b.
180 ­ 173.82
Homework: 13/ 2­18 x2, 31, 34­37, 42­46 x2