Abacus Lesson 33: Subtraction, Compound Complementary Numbers, 100's column

872 - 216
100's column, take away 2
10's column, take away 1
1's column, Compound complement of 6 is 1
Take away 1, add 5, take away 1 in 10's column
Answer is 656

Abacus Lesson 32: Subtraction, Compound Complementary Numbers, 10's column

73 - 18
10's column, take away 1
1's column, Compound complement of 8 is 3
Take away 3, add 5, take away 1 in 10's column (carry)
Answer is 55

Abacus Lesson 31: Subtraction, Compound complementary Numbers, 10's column

13 - 6 (13 minus 6)
Addition involving subtraction of complements of 6
Complement of 6 is 4, complement of 4 w.r.t. 5 is 1
Add 1, take away 5, add 10
Subtraction, do opposite of above,
Take away 1, add 5, take away 10
Answer is 7

Abacus Lesson 30: Addition, Compound Complements of 10, 100's column

267 + 165
Add 1 in the 100's column
Complement of 6 is 4, complement of 4 w.r.t. 5 is 1
Add 1, take away 5, add 1 in next column (carry 1)
Complement of 5 is 5, take away 5, add 1 in next column (carry 1)
Answer is 432

Abacus Lesson 29: Addition, Compound Complements of 10, 10'ss column

15 + 26
Do left to right. Add 2 in 10's column
Complement of 6 is 4, complement of 4 w.r.t. 5 is 1
Add 1, take away 5, add 10
Answer is 41

Abacus Lesson 28: Addition, Compound Complements of 10, 1's column

6 + 7
Complement of 7 is 3, complement of 3 w.r.t. 5 is 2
Add 2, take away 5, add 10
Answer is 13

Abacus Lesson 27: Subtractions using complements of 10, 100's column

Video Abacus Lesson 27: Subtractions using complements of 10, 100's column (Click Read more, then click video link

423 - 299 (423 minus 299)
Start from left to right
In the 100's column, take away 2
In the 10's column, complement if 9 is 1, add 1 in 10's column, take away 1 in 100's column
In the 1's column, complement of 9 is 1, add 1 in the 1's column, take away 1 in the 10's column
Answer is 124

Abacus Lesson 20: Subtraction, Complements of 5, 100's column

125 - 11 (125 take away 11)
365 - 13 (365 minus 13)
255 - 104 (255 subtract 104)

297 - 133 (297 take away 133)
245 - 211 (245 minus 211)

Now do the worksheet

Video: Abacus Lesson 20: Subtraction, Complements of 5, 100's column

Acknowledgement: Credit to John of HEV Project for the abacus lesson videos and worksheet

Abacus Lesson 19: Subtraction, Complements of 5, 10's column

15 - 4 (15 take away 4)
Not enough beads, complement of 4 is 1, add 1, take away 5, Answer 11

Abacus Lesson 18: Subtraction, Complements of 5, 1's column

(complements of 5)
Addition: subtract complement, add 5
Subtraction: add complement, take away 5

5 - 3 (5 minus 3)
Complement of 3 is 2, add 2, take away 5)

Abacus Lesson 17: Simple Subtraction (0-10) 100's column

245 - 125 (245 take away 125)
193 - 151 (193 minus 151)
986 - 555 (986 subtract 555)

Abacus Lesson 16: Simple Subtraction (0-10) 10's column

92 - 51 (92 take away 51)
89 - 25 (89 minus 25)
75 - 25 (75 subtract 25)

Abacus Lesson 15: Simple Subraction (0-10) 1's column

9 - 5 (9 take away 5)
8 - 5 (8 minus 5)
7 - 5 (7 subtract 5)

Abacus Lesson 14: Simple Subtraction (0-5 only) 100's column

241 - 101 (241 take away 101)
433 - 211 (433 minus 211)
141 - 121 (141 subtract 121)

Abacus Lesson 13: Simple Subtraction (0-5 only) 10's column

44 - 22 (44 take away 22)
34 - 10 (34 minus 10)
22 - 12 (22 subtract 12)
44 - 13 (44 take away 13)


Now do the worksheet

Video: Abacus Lesson 13: Simple Subtraction (0-5 only) 10's column



Acknowledgement: Credit John of HEV Project. This post is a summary of HEV Abacus Lessons

Abacus Lesson 12: Simple Subtraction (0-5 only) 1's column

Addition: move beads to touch center beam
Subtraction: move beads away from center beam

3 - 1 (3 take away 1)
2 - 2 (2 minus 2)

Abacus Lesson 11: Addition, Complements of 5, 100's column

101 + 234 (101 plus 234)
Do from left to right
Add 2 in 100's column
Add 3 in 10's column
Complement of 4 is 1, take away 1 in 1's column, add 5
Answer is 335

Abacus Lesson 10: Addition, Complements of 5, 10's column

11 + 4 (11 plus 4)
Complement of 4 is 1
Take away 1, add 5
Answer is 15

Abacus Lesson 9: Addition, Complements of 5, 1's column

Complements of a number are 2 numbers which together adds up to the first number.
Complements of a 5 are 2 numbers which together adds up to 5.
Complements of 5 are 4 & 1, 3 & 2, 2 & 3, 1 & 4
We use complements when we run out of earthly beads

For additions, we take away complements when we are doing additions.

Abacus Lesson 8: Simple additions, 100's column

412 + 51
321 + 122
491 + 507

Abacus Lesson 7: Simple Addition, 10's column

10 + 5
55 + 2
24 + 5

Abacus Lesson 6: Simple additions using earthly and heavenly beads

2 + 5
1 + 5
1 + 6

Abacus Lesson 5: Simple additions, 100's column

231 + 111
Start from left to right
Add 1 in 100's column, then add 1 in 10's column, then add 1 in 1's column
123 + 321

Abacus Lesson 4: Simple additions, 10's column

This lesson is just about using abacus to do simple addition. For example 11 + 2
1 early bead in 10's column, 1 earthly bead in 1's column to represent number 11 To add 2 to above, just move 2 earthly bead up in the 1's column Answer is 1 earthly bead in 10's column, 3 earthly beads in 1's column Answer is 13 If not clear about the above example and if you want to view how to do the examples below, view the video at the bottom of this webpage (click "Read more") 12 + 2
41 + 3

Abacus Lesson 3: Simple additons, 0 to 5 only

First column with the dot is the 1's column
Use this column for 0 to 9

Simple addition 1 + 3
Add 1 earthly beads
Add 3 earthly beads
Answer is 4

Abacus Lesson 2: Counting on the abacus

First number is zero
No beads touching the beam, that is zero

1 is 1 bead in the earthly beads
2 is 2 beads in the earthly beads
3 is 3 beads in the earthly beads

Abacus Lesson 26: Subtractions using complements of 10, 10's column

Video: Abacus Lesson 26: Subtractions using complements of 10, 10's column (click Read more, then click this link)

43 - 19 (43 take away 19)
Start from left to right
Take away 1 in 10's column
Complement of 9 is 1, add 1 in 1's column, take away 1 in 10's column
Answer is 24

22 - 8 (22 minus 8)
Complement of 8 is 2, add 2 in 1's column, take away 1 in 10's column
Answer is 14

Abacus Lesson 25: Subtraction, complements of 10, 1's column

Video: Abacus Lesson 25: Subtraction, complements of 10, 1's column
For subtraction, add complement of tens in 1's column, take away 1 in 10's column

10 - 7 (10 take away 7)
Complement of 7 is 3, add 3 in 1's column, subtract 1 in 10's column
Answer is 3

10 - 6 (10 minus 6)
Complement of 6 is 4, add 4 in 1's column, take away 1 in 10's column
Answer is 4

Abacus Lesson 25: Subtraction: Complementary Numbers Respect to 10'S Column

AbacusVideo: Lesson 25: Subtraction: Complementary Numbers Respect to 10'S Column

10 - 7 (10 subtract 7)
In the 1's column, complement of 7 is 3, add 3 in 1s column, take away 1 in the 10's column
Answer is 3

10 - 6 (10 subtract 6)
In the 1's column, complement of 6 is 4, add 4 in the 1's column, subtract 1 in 10's column
Answer is 4

Abacus Lesson 24: Addition, Complementary Numbers Respect to 100'S Column

Abacus Lesson 24: Addition - Complementary Numbers Respect to 100'S Column

364 + 107
Do from left to right, do the 100s column, then the 10s column, then the 1s column
In the 100s column add 1
In the 10s column, add nothing
In the 1s column, complement of 7 is 3
Take away 3 in the 1s column, add 1 in the 10s column
Answer is 471