Math problems.

WALT add and subtract numbers involving decimals

Make sure you show how you worked it out! Using brackets ( ) to expand numbers out

1. 3.4 + 6.7 = 10.1

(3 + 6 =9) (0.4 + 0.7= 1.1)

2. 12.8 + 9 =21.8

(12+9=21) (0.8+0.0=0.8)

3. 23.2 + 38.5 = 61.7

(20+30=50)(3+8=11) (0.2+0.5=0.7)

4. 10 + 0.7 = 10.7

(10+0=10) (0.0 + 0.7=0.7)

5. 47.5 + 61.8 =109.3

(40+60=100)(7+1=8) (0.5 + 0.8=1.3)

6. 18 + 4.8 =22.8

(10+0=10)(8 + 4=12) (0.0 + 0.8=0.8)

7. 33.5 + 7.6 = 41.1

(30+0=30)(3+7=10)(0.5+0.6=1.1)

8. 68 + 12.3 =80.3

(60+10=70)(8+2=10)(0.0+0.3=0.3)

9. 19.5 + 19.5 =39

(10+10=20)(9+9=18)(0.5+0.5=1)

10. 172 + 17.2 = 189.2

(100+0=100)(70+10=80)(2+7=9)(0.0+0.2)

11. 23.3 + 4.4 = 27.7

(20+0=20)(3+4=7)(0.3+0.4=0.7)

12. 101 + 110.1 = 211.1

(100+100=200)(0+10=10)(1+0=1)(0.0+0.1=0.1)

SUBTRACTION!!!!!

1. 8.3 - 6.6 = 2.3

(8-6=2)(0.3-0.6=0.3)

2. 13.7 - 9 = 4.7

(13-9=4)(0.7-0.0=0.7)

4.7

3. 29.9 - 10.5 = 19.4

(20-10=10)(9-0=9)(0.9-0.5=0.4)

4. 10 - 4.7 = 6

(10-4=6)(0.0-0.7=0.0)

5. 40.4 - 1.9 =39.5

(40-1=39)(0.4-0.9=0.5)

6. 11.6 - 3.8 =8.2

(11-3=8)(0.6-0.8=0.2)

7. 37.2 - 3.1 =34.1

(37-3=34)(0.2-0.1=0.1)

8. 68.4 - 22.3 =46.1

(68-22=46)(0.4-0.3=0.1)

9. 30 - 17.5 = 13.05

(30-17=13)(0.0-0.5=0.05

10. 262 - 26.2 = 236

(262-26=236)(0.0-0.2=0.0)

11. 503.3 - 54.4 =449.1

(503-54=449)(0.3-0.4=0.1)

12. 903 - 130.8 = 773.3

(903 - 130 =773)(0.0-0.3=0.3)