Using Rounding/Compatible numbers to estimate

Estimate the product using compatible numbers.

24×37

• 24x37=888

• 30x40=1,200

• 25x40=1,000

• 20x30=600

Tags

CCSS.4.NBT.B.5

Mason swims about 55 minutes each day. Estimate the

number of minutes he swims in 14 days.

• 60x10=600 minutes

• 50x10=500 minutes

• 60x20=1,200 minutes

• 50x20=1,000 minutes

Tags

CCSS.4.NBT.B.5

CCSS.4.MD.A.2

CCSS.4.OA.A.2

24×18 rounds to

• 30x20=600

• 20x20=400

• 20x10=200

• 30x10=300

Tags

CCSS.4.NBT.B.5

39×19 rounds to

• 30x20=600

• 30x10=300

• 40x20=800

• 40x10=400

Tags

CCSS.4.NBT.B.5

Estimate the product using compatible numbers.

52×27

• 50x25=1,250

• 50x20=1,000

• 52x27=1,404

• 60x30=1,800

Tags

CCSS.4.NBT.B.5

Rounding means

• add
• to move the numbers up or down depending on the place value 
• moving

Tags

CCSS.3.NBT.A.1

CCSS.4.NBT.A.3

Numbers that are easy to add and subtract

• Adding Numbers

• Compatible Numbers

• Easy Numbers

Tags

CCSS.4.NBT.B.4