Cogito
Grade 8 Math · Chapter 8 · Lesson 3
Placing an Irrational Number
Trapping √2 between two numbers you know.
10 problems · about 19 minutes · 8.NS.A.2
Figure — use these to answer the problems
1
Warm-Up Review
From earlier lessons. Loosen up before the new work.
3 problemsFrom “Cube Roots”
Cube root of 216?
AnswerFrom “Square Roots and Irrational Numbers”
What is √100?
AnswerFrom “Calculating in Scientific Notation”
(4 × 10⁵) × (2 × 10³). What is the exponent?
Answer
Warm Up
Straightforward practice. Get the method working first.
3 problems√40 lies between which two whole numbers? Give the smaller.
Answer√8 lies between which two whole numbers? Give the smaller.
Answer√30 lies between which two whole numbers? Give the smaller.
Answer
Build It Up
The same ideas with more to keep track of.
2 problems√49 exactly. What is it?
AnswerDoes the decimal for √2 ever repeat? 1 for yes, 0 for no.
Answer
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsThe Trap
√5 lies between which two whole numbers? Give the smaller one.
AnswerThe Bigger One
√20 lies between which two whole numbers? Give the smaller one.
Answer