1.NBT.4 — Adding Within 100: Two-Digit & One-Digit Numbers
Practice adding a two-digit number and a one-digit number, or a two-digit number and a multiple of 10, using place-value strategies to find sums within 100.
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Three different problem sets — same skill, same layout, fresh numbers.
Preview — Set A
Solve each addition problem and write the answer on the line.
- 1.23+5
- 2.41+8
- 3.30+40
- 4.56+3
- 5.20+50
- 6.74+4
- 7.60+30
- 8.15+7
- 9.43+20
- 10.82+6
- 11.50+40
- 12.67+2
- 13.34+50
- 14.11+9
- 15.25+30
- 16.48+1
- 17.70+20
- 18.53+6
- 19.62+30
- 20.37+2
- 21.44+40
- 22.91+7
What this worksheet covers
22 addition problems fill this vertical format page; problem 8 asks "15 + 7", and the sheet stays at that level throughout. Two of the 22 column problems need regrouping and the rest do not, so the two cases are mixed rather than blocked and the numbers run as high as 91. Further down, problem 15 asks "25 + 30". Common Core 1.NBT.4 is the slot this page fills.
Skills practised
The grade 1 addition sequence covers fact fluency within 20, three addends, and two-digit plus one-digit numbers; this page sits inside it. What a student is asked to do here is adding Within 100: Two-Digit & One-Digit Numbers. To finish it, a student has to regroup past ten rather than counting up one at a time. Sixteen different answers appear across the 22 problems, so a student cannot copy one result down the page.
About the vertical format format
The 22 problems here — problem 8, "15 + 7", for one — are printed in column form, the layout the standard algorithm is written for. Stacked operands make the place-value columns visible, which is what regrouping actually depends on.
Set A, Set B and Set C
Set A is the original MathSheetLab worksheet; Sets B and C keep its structure and redraw the numbers, with each answer recomputed rather than copied. Where Set A's problem 12 is "67 + 2", Set B's is "79 + 6".
How to use this worksheet
Grade 1 attention runs short, so split these 22 addition problems over two or three sittings rather than pushing through in one; a number line or counters within reach is a strategy, not a failure. Print Set B of this addition vertical format before writing on Set A; the same skill worked twice a week apart tells you far more than once.
One mistake to watch for
Regrouping is skipped: 47 + 38 is answered as 715. Problem 15 on this grade 1 vertical format page, "25 + 30", is where to look for it.
Each column is treated as its own one-digit problem with no place-value structure joining them.
Return to expanded form for a few days and ask what 7 + 8 is worth; fifteen ones cannot sit in the ones column.
Other grade 1 addition formats
The same skill in the other formats available at this grade.
- Drill — Grade 1 Addition Practice, 18 problems
- Timed Drill — Grade 1 Addition Timed Drill, 60 problems
- Missing Number — Grade 1 Addition Missing Number, 24 problems
- Mixed Review — Adding Three Numbers — Grade 1 Word Problems, 22 problems
- Word Problems — Adding Up: Grade 1 Word Problems Within 20, 22 problems
A step either side
The same format one grade down and one grade up — the easier sheet is often the faster fix when this one is not landing.
- Kindergarten Addition Vertical Format — kindergarten, 16 problems
- 2.NBT.7 — Adding Within 1000 Practice — grade 2, 20 problems
Vertical Format sheets in other grade 1 topics
Six PDFs, no sign-up: three versions of this grade 1 addition vertical format and three answer keys, each 22 problems long.