Question

b147b
(9)
\

$$\begin{array}{r} 61 \\\\ - 21 \\\\ \\hline 40 \\end{array}$$

(14)
\

$$\begin{array}{r} 64 \\\\ - 35 \\\\ \\hline \\end{array}$$

(10)
\

$$\begin{array}{r} 61 \\\\ - 28 \\\\ \\hline \\end{array}$$

(15)
\

$$\begin{array}{r} 64 \\\\ - 37 \\\\ \\hline \\end{array}$$

(11)
\

$$\begin{array}{r} 61 \\\\ - 46 \\\\ \\hline \\end{array}$$

(16)
\

$$\begin{array}{r} 64 \\\\ - 59 \\\\ \\hline \\end{array}$$

(12)
\

$$\begin{array}{r} 61 \\\\ - 43 \\\\ \\hline \\end{array}$$

(17)
\

$$\begin{array}{r} 64 \\\\ - 58 \\\\ \\hline \\end{array}$$

(13)
\

$$\begin{array}{r} 61 \\\\ - 47 \\\\ \\hline \\end{array}$$

(18)
\

$$\begin{array}{r} 64 \\\\ - 62 \\\\ \\hline \\end{array}$$

b148a kumon
subtraction of 2-digit numbers 3
subtract
(1)
\

$$\begin{array}{r} 72 \\\\ - 31 \\\\ \\hline \\end{array}$$

(5)
\

$$\begin{array}{r} 75 \\\\ - 46 \\\\ \\hline \\end{array}$$

(2)
\

$$\begin{array}{r} 72 \\\\ - 30 \\\\ \\hline \\end{array}$$

(6)
\

$$\begin{array}{r} 75 \\\\ - 44 \\\\ \\hline \\end{array}$$

(3)
\

$$\begin{array}{r} 72 \\\\ - 32 \\\\ \\hline \\end{array}$$

(7)
\

$$\begin{array}{r} 75 \\\\ - 47 \\\\ \\hline \\end{array}$$

(4)
\

$$\begin{array}{r} 72 \\\\ - 47 \\\\ \\hline \\end{array}$$

(8)
\

$$\begin{array}{r} 75 \\\\ - 69 \\\\ \\hline \\end{array}$$

Explanation:

<pre_analysis>
{
"quality": "clear",
"question_count": 18,
"skills_matched": [
"step_cot",
"table_formatter",
"explain_then_answer",
"quick"
],
"needs_drawing": false,
"concepts_used": [
"Column Subtraction",
"Subtraction with Regrouping"
],
"new_concepts": [],
"current_concepts": [
"Column Subtraction",
"Subtraction with Regrouping"
]
}
</pre_analysis>

<reasoning>

Calculate page B147b column 1

\[

$$\begin{aligned} (9)\quad &61 - 21 = 40 \\ (10)\quad &61 - 28 = 33 \\ (11)\quad &61 - 46 = 15 \\ (12)\quad &61 - 43 = 18 \\ (13)\quad &61 - 47 = 14 \end{aligned}$$

\]

Calculate page B147b column 2

\[

$$\begin{aligned} (14)\quad &64 - 35 = 29 \\ (15)\quad &64 - 37 = 27 \\ (16)\quad &64 - 59 = 5 \\ (17)\quad &64 - 58 = 6 \\ (18)\quad &64 - 62 = 2 \end{aligned}$$

\]

Calculate page B148a columns 1 and 2

\[

$$\begin{aligned} (1)\quad &72 - 31 = 41 \\ (2)\quad &72 - 30 = 42 \\ (3)\quad &72 - 32 = 40 \\ (4)\quad &72 - 47 = 25 \\ (5)\quad &75 - 46 = 29 \\ (6)\quad &75 - 44 = 31 \\ (7)\quad &75 - 47 = 28 \\ (8)\quad &75 - 69 = 6 \end{aligned}$$

\]
</reasoning>

<answer>

No.	Problem	Answer
(10)	\(61 - 28\)	\(33\)
(11)	\(61 - 46\)	\(15\)
(12)	\(61 - 43\)	\(18\)
(13)	\(61 - 47\)	\(14\)
(14)	\(64 - 35\)	\(29\)
(15)	\(64 - 37\)	\(27\)
(16)	\(64 - 59\)	\(5\)
(17)	\(64 - 58\)	\(6\)
(18)	\(64 - 62\)	\(2\)
(1)	\(72 - 31\)	\(41\)
(2)	\(72 - 30\)	\(42\)
(3)	\(72 - 32\)	\(40\)
(4)	\(72 - 47\)	\(25\)
(5)	\(75 - 46\)	\(29\)
(6)	\(75 - 44\)	\(31\)
(7)	\(75 - 47\)	\(28\)
(8)	\(75 - 69\)	\(6\)

</answer>

<post_analysis>
{
"subject": "Mathematics",
"question_type": "Free Response",
"knowledge_point": [
"Mathematics",
"Algebra",
"Column Subtraction"
]
}
</post_analysis>

Answer:

<pre_analysis>
{
"quality": "clear",
"question_count": 18,
"skills_matched": [
"step_cot",
"table_formatter",
"explain_then_answer",
"quick"
],
"needs_drawing": false,
"concepts_used": [
"Column Subtraction",
"Subtraction with Regrouping"
],
"new_concepts": [],
"current_concepts": [
"Column Subtraction",
"Subtraction with Regrouping"
]
}
</pre_analysis>

<reasoning>

Calculate page B147b column 1

\[

$$\begin{aligned} (9)\quad &61 - 21 = 40 \\ (10)\quad &61 - 28 = 33 \\ (11)\quad &61 - 46 = 15 \\ (12)\quad &61 - 43 = 18 \\ (13)\quad &61 - 47 = 14 \end{aligned}$$

\]

Calculate page B147b column 2

\[

$$\begin{aligned} (14)\quad &64 - 35 = 29 \\ (15)\quad &64 - 37 = 27 \\ (16)\quad &64 - 59 = 5 \\ (17)\quad &64 - 58 = 6 \\ (18)\quad &64 - 62 = 2 \end{aligned}$$

\]

Calculate page B148a columns 1 and 2

\[

$$\begin{aligned} (1)\quad &72 - 31 = 41 \\ (2)\quad &72 - 30 = 42 \\ (3)\quad &72 - 32 = 40 \\ (4)\quad &72 - 47 = 25 \\ (5)\quad &75 - 46 = 29 \\ (6)\quad &75 - 44 = 31 \\ (7)\quad &75 - 47 = 28 \\ (8)\quad &75 - 69 = 6 \end{aligned}$$

\]
</reasoning>

<answer>

No.	Problem	Answer
(10)	\(61 - 28\)	\(33\)
(11)	\(61 - 46\)	\(15\)
(12)	\(61 - 43\)	\(18\)
(13)	\(61 - 47\)	\(14\)
(14)	\(64 - 35\)	\(29\)
(15)	\(64 - 37\)	\(27\)
(16)	\(64 - 59\)	\(5\)
(17)	\(64 - 58\)	\(6\)
(18)	\(64 - 62\)	\(2\)
(1)	\(72 - 31\)	\(41\)
(2)	\(72 - 30\)	\(42\)
(3)	\(72 - 32\)	\(40\)
(4)	\(72 - 47\)	\(25\)
(5)	\(75 - 46\)	\(29\)
(6)	\(75 - 44\)	\(31\)
(7)	\(75 - 47\)	\(28\)
(8)	\(75 - 69\)	\(6\)

</answer>

<post_analysis>
{
"subject": "Mathematics",
"question_type": "Free Response",
"knowledge_point": [
"Mathematics",
"Algebra",
"Column Subtraction"
]
}
</post_analysis>