5.6 Using Reasonableness

Ursula has an album in which she keeps pressed flowers. The album has 34 pages, and each page has 7 pressed flowers. Which of the following shows a reasonable estimate of how many pressed flowers Ursula has?

• 30 x 7 = 210

• 40 x 7 = 280

• 50 x 5 = 250

• 60 x 4 = 240

Tags

CCSS.4.NBT.B.5

Isabelle has 9 ant farms. Each ant farm has 99 ants. Which of the following shows a reasonable estimate of how many ants Isabelle has?

• 7 x 125 = 875

• 8 x 110 = 880

• 9 x 100 = 900

• 10 x 100 = 1,000

Tags

CCSS.4.NBT.B.5

At an athletic club there are 11 people on a sports team. There are 8 teams. About how many people are on teams?

• About 80

• About 70

• About 50

• About 50

Tags

CCSS.4.NBT.B.5

Kenny has 7 pouches. Each pouch has 21 marbles. About how many marbles does Kenny have?

• 200

• 140

• 100

• 70

Tags

CCSS.3.OA.A.3

CCSS.3.OA.A.1

CCSS.3.OA.C.7

CCSS.3.OA.B.5

Viktor has 7 piles of coins with 63 coins in each. Which is a reasonable number of coins in Viktor’s piles?

• 300, because 7 × 63 is about 7 × 40 = 280

• 360, because 7 × 63 is about 7 × 50 = 350.

• 441, because 7 × 63 is about 7 × 60 = 420.

• 500, because 7 × 63 is about 7 × 70 = 490

Tags

CCSS.3.OA.A.3

CCSS.3.OA.D.8

CCSS.3.OA.A.1

How tall will the sunflower be after the 5th week if it continues to grow at the same rate?

Tags

CCSS.HSF.BF.A.2

Marisa says 302 × 6 = 192. Which of the following shows a reasonable estimate?

• 400x6=2,400

• 300x6=1,800

• 300x10=3,000

• 300x6=900

Tags

CCSS.3.OA.D.8

CCSS.3.NBT.A.1

Jaime practiced swimming for about 11 hours every week for 8 weeks. Which equation would you use to check for reasonableness?

• 10x10=100

• 20x8=160

• 10x8=80

• 11x8=89

Tags

CCSS.3.OA.A.3

CCSS.3.OA.D.8

CCSS.3.OA.C.7