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Rounding & Estimating
Formulas
Equations w/decimals
Vocab
100
Round to the hundredths place: 121.1237
What is 121.12
100
d = rt when r = 35 mi/hr and t = 2 hr
What is d = 70 mi.
100
y - 1.56 = 1.64
What is y = 3.2
200
Round to the tenths place 0.4821
What is 0.5?
200
A = lw when l = 16 mm and w = 24 mm
What is 384 mm sq.
200
n + 3.8 = 10.9
What is n = 7.1
300
Estimate the sum 2.8 + 3.6
What is 7?
300
Perimeter of a square: P = 4s when s = 13 cm
What is 52 cm
300
c/12.5 = 77.5
What is c = 968.75
400
Estimate 5.62 x 1.89
What is 12?
400
Perimeter of rectangle P = 2l + 2w for length = 10 and width = 5
What is P = 30 units
400
3.8 = x + 12.9
What is x = -9.1
400

Formula

An equation that shows a relationship between quantities represented by variables. 
500

Estimate 98.6 / 9.53

What is 10?

500
A = lw length = 14 cm width = 7 cm
What is 98 cm sq
500
-5.7x = 110.58
What is x = -19.4
500

Compatible Numbers

Numbers that are easy to divide mentally.