Exercise 7

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

In this practice session, our main objective is to excel in addition and subtraction within the range 1 to 99.

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

In the 7th exercise:

+9 = +10 –1
+8 = +10 –2
+7 = +10 –3
+6 = +10 –4
+5 = +10 –5
+4 = +10 –6
+3 = +10 –7
+2 = +10 –8
+1 = +10 –9
-9 = -10 +1
-8 = -10 +2
-7 = -10 +3
-6 = -10 +4
-5 = -10 +5
-4 = -10 +6
-3 = -10 +7
-2 = -10 +8
-1 = -10 +9

Exercise 7.1

5 + 11 + 11 = ?

+ 11 =

Congratulations if your response equals 27

Exercise 7.2

13 - 13 + 12 - 9 + 12 - 7 + 7 + 9 + 13 = ?

- 13 =

+ 12 =

- 9 = 12 - 10 + 1 =

+ 12 =

- 7 = 15 - 10 + 3 =

+ 7 = 8 + 10 - 3 =

+ 9 = 15 + 10 - 1 =

+ 13 =

Congratulations if your response equals 37

Exercise 7.3

3 + 12 + 13 - 4 - 9 + 8 + 13 - 17 - 5 - 12 + 9 + 8 = ?

+ 12 =

+ 13 =

- 4 =

- 9 = 24 - 10 + 1 =

+ 8 = 15 + 10 - 2 =

+ 13 =

- 17 =

- 5 =

- 12 =

+ 9 = 2 + 10 - 1 =

+ 8 =

Congratulations if your response equals 19

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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