Vocab/Important
What is the first step of adding and subtracting decimals?
LINE UP THE DECIMAL POINTS
Estimate the sum of $6.29, $41.35, and $12.65 by rounding each number to the nearest whole number.
$60
3.88 + 2.7
6.58
What numbers make it easier to compute with mental math?
Compatible numbers
Two rock samples have masses of 44.24 grams and 9.98 grams. What is the estimated total mass if you round the decimals to the nearest tenth?
54.2 grams
2.607 +4.13+17.2
23.937
17.999-8.0
9.999
What is the process where you adjust one number to make a computation easier and balance the adjustment by changing another number?
Compensation
The classroom is 26.15 feet long and 15.62 feet wide. Round the length and width to the nearest whole number. Then estimate the perimeter of the classroom.
84 ft.
4.17+2.2+199.087
205.457
13.58-6.962
6.618
Which property states that addends can be regrouped and the sum remains the same?
Associative Property of Addition
In the track meet, Jane ran 1500m. When Jane finished, Sarah still had 272.6m left. Round the numbers to the nearest whole number. Estimate how many meters Sarah has already run.
1,227m
2.63+98.7203+4.70
106.0503
7.87-6.230
1.64
Which property states that addends can be added in any order and the sum remains the same?
Commutative Property of Addition
James treat cost $6.58. Olivia's treat cost $4.13. Estimate the total by rounding each number to the nearest whole number. What is the total?
$11
47.356+2+13.79
63.146
12.372-6.41-2
3.962