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
- 1.57 + 19 =
- 2.345 + 99 =
- 3.53 − 29 =
- 4.49 + 9 =
- 5.77 − 29 =
- 6.74 − 9 =
- 7.37 − 19 =
- 8.91 − 19 =
- 9.201 + 99 =
- 10.49 − 29 =
- 11.41 + 19 =
- 12.18 − 9 =
- 13.107 − 29 =
- 14.40 + 19 =
- 15.12 + 9 =
- 16.37 − 9 =
- 17.67 − 9 =
- 18.34 − 29 =
- 19.613 − 99 =
- 20.55 − 9 =
- 21.46 − 29 =
- 22.497 + 99 =
- 23.45 − 29 =
- 24.55 + 9 =
- 25.228 + 99 =
- 26.87 − 29 =
- 27.54 + 19 =
- 28.623 − 99 =
- 29.58 + 29 =
- 30.44 + 19 =
- 31.64 + 19 =
- 32.265 + 99 =
- 33.87 − 9 =
- 34.58 + 9 =
- 35.185 + 99 =
- 36.25 − 9 =
- 37.74 − 19 =
- 38.532 − 99 =
- 39.33 − 29 =
- 40.62 + 29 =
Answer key
- 76
- 444
- 24
- 58
- 48
- 65
- 18
- 72
- 300
- 20
- 60
- 9
- 78
- 59
- 21
- 28
- 58
- 5
- 514
- 46
- 17
- 596
- 16
- 64
- 327
- 58
- 73
- 524
- 87
- 63
- 83
- 364
- 78
- 67
- 284
- 16
- 55
- 433
- 4
- 91
Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths