Question

complete to solve 47 + 23.
47 + 23
= 47 + (□ + 20)
= (47+□) + 20
= □ + 20
= □

Explanation:

Step1: Decompose 23

We know that \(23 = 3 + 20\), so we fill the first box with 3.
\(47 + 23 = 47+(3 + 20)\)

Step2: Apply associative property

Using the associative property of addition \((a + b)+c = a+(b + c)\), we can rewrite the expression as \((47 + 3)+20\). So the second box is also 3.
\(47 + 23=(47 + 3)+20\)

Step3: Calculate 47 + 3

Calculate \(47+3 = 50\). So the third box is 50.
\(47 + 23=50+20\)

Step4: Calculate 50 + 20

Calculate \(50 + 20=70\). So the fourth box is 70.

Answer:

The first box: \(3\), the second box: \(3\), the third box: \(50\), the fourth box: \(70\) (and the final result of \(47 + 23\) is \(70\))