Doubles, Near Doubles, and Adding Three Numbers Using Doubles and Near Doubles

Doubles

100

1+1

2

200

2+2

4

300

4+4

8

400

7+7

14

500

9+9

18

Near Doubles

100

1+2

3

200

2+3

5

300

4+5

9

400

6+7

13

500

8+9

17

Doubles Riddles

100

1+?=2

1

200

2+?=4

2

300

5+?=10

5

400

7+?=14

7

500

9+?=18

9

Near Doubles Riddles

100

1+?=3

2

200

4+?=9

5

300

7+?=15

8

400

9+?=19

10

500

10+?=21

11

Adding Three Numbers

100

1+1+2

4

200

3+3+4

10

300

5+5+3

13

400

7+8+1

16

500

8+9+2

19