Topic 2: Number Sense

Addition Properties

100

17+25=42

Which numbers are the Addends?

17 and 25

200

17+25=42

Which number is the sum?

42

300

5+0=5

Which property of addition is shown above?

Identity (zero) property of addition

400

7+5=5+7

Which property of addition is shown above?

Commutative (order) property of addition

500

(3+4)+5=12      3+(4+5)=12

Which property of addition is shown above?

Associative (grouping) property of addition

Subtraction

100

140-129=11

Which number is the difference?

11

200

187-29=

158

300

Pat has 265 pins. Chris has 139 pins. How many more pins does Pat have than Chris?

265-139=126

126 more pins

400

Carrie invited 13 girls to a party. Five of the girls have already arrived. How many more girls are still coming?

13-5=8

8 more girls

500

5+4=9

4+5=9

9-5=4

9-4=5

A group of related facts using the same numbers are called _________

Fact Family

Using Mental Math

100

71+13=

84

200

27-20=

7

300

62+34=

96

400

72-19=

53

500

66-18=

48

Rounding

100

Round 258 to the nearest hundred

300

200

Round 727 to the nearest ten

730

300

round to the nearest hundred, then add 

198+426=

200+400=600

400

Round to the nearest hundred, then subtract

361-117=

400-100=300

500

Round to the nearest ten and then subtract

186-115=

190-120=70