Step-by-step Maths Level 2: Missing parts in bonds to 20

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 11
2. Take the known part away from the whole. What is left is the missing part.
   20 - 11 = 9
3. Write the missing part.
   9

Check. 11 and 9 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 10
2. Take the known part away from the whole. What is left is the missing part.
   20 - 10 = 10
3. Write the missing part.
   10

Check. 10 and 10 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 12
2. Take the known part away from the whole. What is left is the missing part.
   20 - 12 = 8
3. Write the missing part.
   8

Check. 12 and 8 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 19
2. Take the known part away from the whole. What is left is the missing part.
   20 - 19 = 1
3. Write the missing part.
   1

Check. 19 and 1 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 6
2. Take the known part away from the whole. What is left is the missing part.
   20 - 6 = 14
3. Write the missing part.
   14

Check. 6 and 14 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 9
2. Take the known part away from the whole. What is left is the missing part.
   20 - 9 = 11
3. Write the missing part.
   11

Check. 9 and 11 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 16
2. Take the known part away from the whole. What is left is the missing part.
   20 - 16 = 4
3. Write the missing part.
   4

Check. 16 and 4 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 14
2. Take the known part away from the whole. What is left is the missing part.
   20 - 14 = 6
3. Write the missing part.
   6

Check. 14 and 6 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 18
2. Take the known part away from the whole. What is left is the missing part.
   20 - 18 = 2
3. Write the missing part.
   2

Check. 18 and 2 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 5
2. Take the known part away from the whole. What is left is the missing part.
   20 - 5 = 15
3. Write the missing part.
   15

Check. 5 and 15 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 7
2. Take the known part away from the whole. What is left is the missing part.
   20 - 7 = 13
3. Write the missing part.
   13

Check. 7 and 13 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 2
2. Take the known part away from the whole. What is left is the missing part.
   20 - 2 = 18
3. Write the missing part.
   18

Check. 2 and 18 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 3
2. Take the known part away from the whole. What is left is the missing part.
   20 - 3 = 17
3. Write the missing part.
   17

Check. 3 and 17 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 13
2. Take the known part away from the whole. What is left is the missing part.
   20 - 13 = 7
3. Write the missing part.
   7

Check. 13 and 7 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 1
2. Take the known part away from the whole. What is left is the missing part.
   20 - 1 = 19
3. Write the missing part.
   19

Check. 1 and 19 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.

Method. In a part-whole picture, the two parts add up to the whole.

1. Look at the whole and the known part. The whole is 20.
   20 and 15
2. Take the known part away from the whole. What is left is the missing part.
   20 - 15 = 5
3. Write the missing part.
   5

Check. 15 and 5 make 20. It works.

Watch out. The missing part is never the whole. Find the part by subtracting.