Question
Find the number that makes the equation true.
23 + 7 = ⎕
- 30
- 40
- 50
- 20
Hint:
An addition mental math technique is to dissect an addend. This approach might be more effective for some students than left-to-right addition. This method involves dividing up one addend in an equation into more manageable bits. Here we have given to find the sum of 23 and 7 using mental math. So we will break the number in an appropriate way and then show the sum.
The correct answer is: 30
Now as we know that here we have to find the step by breaking one number. The fact that there are no steps to memorise is one of the best things about mental math. The "friendly number" addition approach facilitates working with large numbers. This is due to the fact that we are, in essence, decomposing the problem into more manageable components.
Friendly numbers are multiples of 10 like 20, 30, 40 which makes the calculations easy. Here we will use the same and then find the step.
Now we have given 23 + 7, let's solve this.
We will break 23 to 20 and 3 first.
20 + 3 + 7
Now add 3 and 7
20 + 10
Finally adding the terms, we get:
30
So, the sum of 23 and 7 is 30.
Here the concept of Break Apart Numbers is used where a number is divided in two parts to make addition easy. The concept of friendly numbers is also used so that it becomes easy for addition or subtraction purpose. So, the first correct step for finding the sum of 28 + 36 mentally is 30.
Related Questions to study
With the help of the image find the sum.
>>> Tens: 60 + 20 = 80
>>> Ones: 2 + 4 = 6
>>> Sum: 80 + 6 = 86
With the help of the image find the sum.
>>> Tens: 60 + 20 = 80
>>> Ones: 2 + 4 = 6
>>> Sum: 80 + 6 = 86
Find the missing ones or tens digits.
15 + 59 = ⎕4
15 + 59 = 74.
Find the missing ones or tens digits.
15 + 59 = ⎕4
15 + 59 = 74.
With the help of the image find the sum.
Tens: 30 + 10 = 40
Ones: 4 + 9 = 13
Sum: 40 + 13 = 53
With the help of the image find the sum.
Tens: 30 + 10 = 40
Ones: 4 + 9 = 13
Sum: 40 + 13 = 53
Find 34 + 49.
*** So, 34 + 49 = 83
Find 34 + 49.
*** So, 34 + 49 = 83
Find the missing ones or tens digits.
17 + 45 = 6⎕
>>> 17 + 45 = 62.
Find the missing ones or tens digits.
17 + 45 = 6⎕
>>> 17 + 45 = 62.
Find the missing number.
Since, the partial division of a number gives ones same as the digit in the one's place.
>>> 82 -> 80 + 2.
Find the missing number.
Since, the partial division of a number gives ones same as the digit in the one's place.
>>> 82 -> 80 + 2.
Find the partial sums:
Tens = 30 + 20 = 50
Ones = 5 + 4 = 9
Find the partial sums:
Tens = 30 + 20 = 50
Ones = 5 + 4 = 9
Find the partial sum of the given place value block.
>>> Tens: 10 + 20 = 30
>>> Ones: 5 + 6 = 11
Find the partial sum of the given place value block.
>>> Tens: 10 + 20 = 30
>>> Ones: 5 + 6 = 11
Find the missing number.
24 - 4 = 20
Find the missing number.
24 - 4 = 20
Find the partial sum of the given place value block.
>>> Tens: 30 + 20 = 50
>>> Ones: 7 + 2 = 9
Find the partial sum of the given place value block.
>>> Tens: 30 + 20 = 50
>>> Ones: 7 + 2 = 9
