Grade 1 · 1.OA.6 · sheet 11 of 30
Addition facts to 20
A printable worksheet, new every day, with a key that names the mistake.
- Twenty facts within twenty: doubles, near doubles, sums that cross ten by making ten first, and a few that do not.
- The key lists what the common shortcut writes when it is left unfinished: 9 + 6 done as 10 + 6.
Addition facts to 20
Write the sum. Use what you know: a double, or make ten first.
- 1 8 + 9 =
- 2 7 + 8 =
- 3 9 + 4 =
- 4 2 + 6 =
- 5 3 + 2 =
- 6 7 + 3 =
- 7 5 + 5 =
- 8 2 + 2 =
- 9 8 + 8 =
- 10 3 + 7 =
- 11 9 + 8 =
- 12 8 + 9 =
- 13 4 + 7 =
- 14 7 + 9 =
- 15 7 + 7 =
- 16 9 + 7 =
- 17 6 + 7 =
- 18 8 + 4 =
- 19 9 + 9 =
- 20 8 + 7 =
The app does this live.
It picks the next problem from the last answer, skips ahead or doubles back, and animates the teaching instead of handing over a rule. Inside the app the same patterns the key names are caught as your child plays.
How to use the key
Mark the sheet against the key. Beside each answer it lists what the known mistakes would have written. One wrong answer is a slip. The same pattern three times is a rule your child is following, and the guide says what to do about it tonight.
On this sheet the key can tell apart: rounding to add, then forgetting to adjust (8 problems).
Cardinal Math watches for all of these, every day.
Inside the app the same patterns are caught as your child plays, across the whole of K to grade 5, and explained to you in plain words. One price, no ads, no streaks. Coming to iPhone and iPad.
Tell me when it's out