Adding 9, 19 and 99 Mental Maths Worksheet
How to do it in your head (Round and adjust): Add 9, 19, 99: add 10, 20, 100, then take 1 away. Take away 9, 19, 99: take away 10, 20, 100, then add 1 back. Ask yourself: did I use too much or too little?
NameDateTime takenScore ___ / 40
- 1.84 − 29 =
- 2.20 + 29 =
- 3.20 − 9 =
- 4.16 + 19 =
- 5.43 + 9 =
- 6.26 + 9 =
- 7.238 − 99 =
- 8.28 − 9 =
- 9.76 − 29 =
- 10.85 − 19 =
- 11.24 − 9 =
- 12.25 + 19 =
- 13.67 + 29 =
- 14.23 + 29 =
- 15.37 + 9 =
- 16.13 + 9 =
- 17.42 + 9 =
- 18.52 + 29 =
- 19.561 − 99 =
- 20.74 + 19 =
- 21.33 + 9 =
- 22.78 + 19 =
- 23.51 + 29 =
- 24.35 + 29 =
- 25.71 + 9 =
- 26.59 − 19 =
- 27.82 − 9 =
- 28.39 − 9 =
- 29.385 − 99 =
- 30.183 + 99 =
- 31.322 − 99 =
- 32.464 + 99 =
- 33.68 + 9 =
- 34.30 + 19 =
- 35.15 + 29 =
- 36.582 − 99 =
- 37.61 − 9 =
- 38.85 − 9 =
- 39.33 − 19 =
- 40.54 + 9 =
Answer key
- 55
- 49
- 11
- 35
- 52
- 35
- 139
- 19
- 47
- 66
- 15
- 44
- 96
- 52
- 46
- 22
- 51
- 81
- 462
- 93
- 42
- 97
- 80
- 64
- 80
- 40
- 73
- 30
- 286
- 282
- 223
- 563
- 77
- 49
- 44
- 483
- 52
- 76
- 14
- 63
Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths