Exercise 4

Basic concepts Exercise 1 Exercise 2 Exercise 3 Exercise 4 Exercise 5 Exercise 6 Exercise 7

In this practice session, we will focus on mastering addition and subtraction within the range of 10, 20, 30, and 40.

Upon each website refresh, a set of 3 random questions will emerge. It is crucial to perform the exercises accurately, swiftly, and with mastery before proceeding to the subsequent exercise.

When adding or subtracting from the thumb of your left or Right hand, the following patterns can be observed:

Right hand: +4 = +5 -1, left hand: +40 = +50 -10
Right hand: +3 = +5 -2, left hand: +30 = +50 -20
Right hand: +2 = +5 -3, left hand: +20 = +50 -30
Right hand: +1 = +5 -4, left hand: +10 = +50 -40
Right hand: -4 = -5 +1, left hand: -40 = -50 +10
Right hand: -3 = -5 +2, left hand: -30 = -50 +20
Right hand: -2 = -5 +3, left hand: -20 = -50 +30
Right hand: -1 = -5 +4, left hand: -10 = -50 +40

Exercise 4.1

40 - 40 + 20 + 10 - 20 + 30 - 10 - 30 + 30 = ?

- 40 =

+ 20 =

+ 10 =

- 20 =

+ 30 =

- 10 =

- 30 =

+ 30 =

Congratulations if your response equals 30

Exercise 4.2

10 + 30 - 30 = ?

+ 30 =

- 30 =

Congratulations if your response equals 10

Exercise 4.3

30 + 10 - 10 - 20 + 30 - 10 + 10 - 40 + 40 - 10 - 20 + 30 - 20 + 20 - 20 + 10 - 30 + 40 = ?

+ 10 =

- 10 =

- 20 =

+ 30 =

- 10 =

+ 10 =

- 40 =

+ 40 =

- 10 =

- 20 =

+ 30 =

- 20 =

+ 20 =

- 20 =

+ 10 =

- 30 =

+ 40 =

Congratulations if your response equals 40

Right hand: +4 = +5 -1, left hand: +40 = +50 -10
Right hand: +3 = +5 -2, left hand: +30 = +50 -20
Right hand: +2 = +5 -3, left hand: +20 = +50 -30
Right hand: +1 = +5 -4, left hand: +10 = +50 -40
Right hand: -4 = -5 +1, left hand: -40 = -50 +10
Right hand: -3 = -5 +2, left hand: -30 = -50 +20
Right hand: -2 = -5 +3, left hand: -20 = -50 +30
Right hand: -1 = -5 +4, left hand: -10 = -50 +40

Basic concepts Exercise 1 Exercise 2 Exercise 3 Exercise 4 Exercise 5 Exercise 6 Exercise 7

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