Mrs Judd's Math Problems

WALT add and subtract numbers involving decimals

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

3.4 + 6.7 = 10.1
(30 + 60 = 90) + (0.4 + 0.7 = 1.1)

12.8 + 9 = 21.8
(10 + 9 = 19) + (0.2 + 0.8 = 1.1)

23.2 + 38.5 = 61.7
(20 + 30 = 50) + (0.3 + 0.8 = 1.1) + (.2 + .5 = 7)

10 + 0.7 = 10.7
(10 + 0 = 10) + (.0 + .7 = 7)

47.5 + 61.8 = 109.3
(400 + 600 = 1000) + (0.7 + 0.1 = 0.8) + (.5 + .8 = 1.3)

18 + 4.8 = 22.8
(18 + 4 = 22) + (.8 + .0 = .8)


33.5 + 7.6 = 41.1
(30 + 7 = 37) + (0.3 + 0.6 = 0.9) + (.5 + .6 = 1.1)


68 + 12.3 = 80.3
(68 + 10 = 78) + (0.2 + 0.0 = 0.2) + (.3)


19.5 + 19.5 = 39
(19 + 19 = 38) + (0.5 + 0.5 = 1.1)


172 + 17.2 = 189.9
(100 + 10 = 110) + (0.7 + 0.7 = 1.4) + (.2 + .2 = 4)

23.3 + 4.4 = 27.7
(20 + 40 = 60) + (0.3 + 0.4 = 0.7) + (.4)

101 + 110.1 = 211.1
(10 + 10 = 20) + (1.0 + 0.1 = 1) + (.1 + .1 = .2)

SUBTRACTION!!!!!

8.3 - 6.6 = 1.7
(80 - 60 = 20) + (0.3 - 0.6 = 0.3)

13.7 - 9 = 4.7
(10 - 9 = 1) + (0.3 + 0.7 = 1)

29.9 - 10.5 = 19.4
(20 - 10 = 10) + (0.9 - 0.0 = 0.9) + (.9 - .5 = .4)

10 - 4.7 = 5.3
(10 - 4 = 6) + (.7)

40.4 - 1.9 = 38.5
(40 - 10 = 30) + (0.4 - 0.9 = 0.5)


11.6 - 3.8 = 7.8
(10 - 3 = 7) + (0.1 - 0.3 = 0.2) + (.6 - .8 = 0.2)


37.2 - 3.1 = 34.1
(30 - 3 = 27) + (0.7 - 0.1 = 0.6) + (.2)


68.4 - 22.3 = 46.1
(60 - 20 = 40) + (0.8 - 0.2 = 0.6) + (.4 - .3 = .1)


30 - 17.5 = 12.5
(30 - 10 = 20) + (0.7 - 0.5 = 0.2)


262 - 26.2 = 235.8
(20 - 20 = 0) + (0.6 - 0.6 = 0) + (0.2 - 0.2 = 0)


503.3 - 54.4 = 448.9
(50 - 50 = 0) + (0 - 4 = 4) + (0.3 - 0.4 = 0.1) + (.4)


903 - 130.8 = 772.2
(90 - 10 = 80) + (0 - 3 = 3) + (0.3 - 0.0 = 0.3) + (.8)