Step-by-step Maths Level 2: Adding a 1-digit number to a 2-digit number

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 11 into 10 and 1. The tens part is 10. The ones part is what is left.
   11 = 10 + 1
2. Add the ones: 1 + 4. Add the ones part to the number that is added.
   1 + 4 = 5
3. Add 10 back. Put the 10 back on the total.
   10 + 5 = 15
4. Write the answer.
   15

Check. Count on 4 from 11: you reach 15.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 13 into 10 and 3. The tens part is 10. The ones part is what is left.
   13 = 10 + 3
2. Add the ones: 3 + 6. Add the ones part to the number that is added.
   3 + 6 = 9
3. Add 10 back. Put the 10 back on the total.
   10 + 9 = 19
4. Write the answer.
   19

Check. Count on 6 from 13: you reach 19.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 14 into 10 and 4. The tens part is 10. The ones part is what is left.
   14 = 10 + 4
2. Add the ones: 4 + 5. Add the ones part to the number that is added.
   4 + 5 = 9
3. Add 10 back. Put the 10 back on the total.
   10 + 9 = 19
4. Write the answer.
   19

Check. Count on 5 from 14: you reach 19.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 10 into 10 and 0. The tens part is 10. The ones part is what is left.
   10 = 10 + 0
2. Add the ones: 0 + 4. Add the ones part to the number that is added.
   0 + 4 = 4
3. Add 10 back. Put the 10 back on the total.
   10 + 4 = 14
4. Write the answer.
   14

Check. Count on 4 from 10: you reach 14.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 11 into 10 and 1. The tens part is 10. The ones part is what is left.
   11 = 10 + 1
2. Add the ones: 1 + 9. Add the ones part to the number that is added.
   1 + 9 = 10
3. Add 10 back. Put the 10 back on the total.
   10 + 10 = 20
4. Write the answer.
   20

Check. Count on 9 from 11: you reach 20.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 14 into 10 and 4. The tens part is 10. The ones part is what is left.
   14 = 10 + 4
2. Add the ones: 4 + 3. Add the ones part to the number that is added.
   4 + 3 = 7
3. Add 10 back. Put the 10 back on the total.
   10 + 7 = 17
4. Write the answer.
   17

Check. Count on 3 from 14: you reach 17.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 17 into 10 and 7. The tens part is 10. The ones part is what is left.
   17 = 10 + 7
2. Add the ones: 7 + 1. Add the ones part to the number that is added.
   7 + 1 = 8
3. Add 10 back. Put the 10 back on the total.
   10 + 8 = 18
4. Write the answer.
   18

Check. Count on 1 from 17: you reach 18.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 12 into 10 and 2. The tens part is 10. The ones part is what is left.
   12 = 10 + 2
2. Add the ones: 2 + 6. Add the ones part to the number that is added.
   2 + 6 = 8
3. Add 10 back. Put the 10 back on the total.
   10 + 8 = 18
4. Write the answer.
   18

Check. Count on 6 from 12: you reach 18.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 10 into 10 and 0. The tens part is 10. The ones part is what is left.
   10 = 10 + 0
2. Add the ones: 0 + 2. Add the ones part to the number that is added.
   0 + 2 = 2
3. Add 10 back. Put the 10 back on the total.
   10 + 2 = 12
4. Write the answer.
   12

Check. Count on 2 from 10: you reach 12.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 15 into 10 and 5. The tens part is 10. The ones part is what is left.
   15 = 10 + 5
2. Add the ones: 5 + 1. Add the ones part to the number that is added.
   5 + 1 = 6
3. Add 10 back. Put the 10 back on the total.
   10 + 6 = 16
4. Write the answer.
   16

Check. Count on 1 from 15: you reach 16.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 17 into 10 and 7. The tens part is 10. The ones part is what is left.
   17 = 10 + 7
2. Add the ones: 7 + 2. Add the ones part to the number that is added.
   7 + 2 = 9
3. Add 10 back. Put the 10 back on the total.
   10 + 9 = 19
4. Write the answer.
   19

Check. Count on 2 from 17: you reach 19.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 12 into 10 and 2. The tens part is 10. The ones part is what is left.
   12 = 10 + 2
2. Add the ones: 2 + 1. Add the ones part to the number that is added.
   2 + 1 = 3
3. Add 10 back. Put the 10 back on the total.
   10 + 3 = 13
4. Write the answer.
   13

Check. Count on 1 from 12: you reach 13.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 10 into 10 and 0. The tens part is 10. The ones part is what is left.
   10 = 10 + 0
2. Add the ones: 0 + 7. Add the ones part to the number that is added.
   0 + 7 = 7
3. Add 10 back. Put the 10 back on the total.
   10 + 7 = 17
4. Write the answer.
   17

Check. Count on 7 from 10: you reach 17.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 18 into 10 and 8. The tens part is 10. The ones part is what is left.
   18 = 10 + 8
2. Add the ones: 8 + 2. Add the ones part to the number that is added.
   8 + 2 = 10
3. Add 10 back. Put the 10 back on the total.
   10 + 10 = 20
4. Write the answer.
   20

Check. Count on 2 from 18: you reach 20.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 12 into 10 and 2. The tens part is 10. The ones part is what is left.
   12 = 10 + 2
2. Add the ones: 2 + 5. Add the ones part to the number that is added.
   2 + 5 = 7
3. Add 10 back. Put the 10 back on the total.
   10 + 7 = 17
4. Write the answer.
   17

Check. Count on 5 from 12: you reach 17.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.

Method. Split the 2-digit number into 10 and the ones. Add the ones, then add 10.

1. Split 16 into 10 and 6. The tens part is 10. The ones part is what is left.
   16 = 10 + 6
2. Add the ones: 6 + 1. Add the ones part to the number that is added.
   6 + 1 = 7
3. Add 10 back. Put the 10 back on the total.
   10 + 7 = 17
4. Write the answer.
   17

Check. Count on 1 from 16: you reach 17.

Watch out. Remember the 10 when you add the ones. 14 + 5 is 19, not 9.