Question

b146b
(9) \

$$\begin{array}{r} 42 \\\\ - 12 \\end{array}$$

(14) \

$$\begin{array}{r} 44 \\\\ - 26 \\end{array}$$

(10) \

$$\begin{array}{r} 42 \\\\ - 10 \\end{array}$$

(15) \

$$\begin{array}{r} 44 \\\\ - 24 \\end{array}$$

(11) \

$$\begin{array}{r} 42 \\\\ - 16 \\end{array}$$

(16) \

$$\begin{array}{r} 44 \\\\ - 29 \\end{array}$$

(12) \

$$\begin{array}{r} 42 \\\\ - 25 \\end{array}$$

(17) \

$$\begin{array}{r} 44 \\\\ - 35 \\end{array}$$

(13) \

$$\begin{array}{r} 42 \\\\ - 28 \\end{array}$$

(18) \

$$\begin{array}{r} 44 \\\\ - 37 \\end{array}$$

b147a kumon
subtraction of 2-digit numbers 3
subtract
(1) \

$$\begin{array}{r} 50 \\\\ - 10 \\end{array}$$

(5) \

$$\begin{array}{r} 55 \\\\ - 32 \\end{array}$$

(2) \

$$\begin{array}{r} 50 \\\\ - 15 \\end{array}$$

(6) \

$$\begin{array}{r} 55 \\\\ - 38 \\end{array}$$

(3) \

$$\begin{array}{r} 50 \\\\ - 24 \\end{array}$$

(7) \

$$\begin{array}{r} 55 \\\\ - 47 \\end{array}$$

(4) \

$$\begin{array}{r} 50 \\\\ - 22 \\end{array}$$

(8) \

$$\begin{array}{r} 55 \\\\ - 49 \\end{array}$$

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 B146b column 1

\[

$$\begin{aligned} (9)\quad &42 - 12 = 30 \\ (10)\quad &42 - 10 = 32 \\ (11)\quad &42 - 16 = 26 \\ (12)\quad &42 - 25 = 17 \\ (13)\quad &42 - 28 = 14 \end{aligned}$$

\]

Calculate page B146b column 2

\[

$$\begin{aligned} (14)\quad &44 - 26 = 18 \\ (15)\quad &44 - 24 = 20 \\ (16)\quad &44 - 29 = 15 \\ (17)\quad &44 - 35 = 9 \\ (18)\quad &44 - 37 = 7 \end{aligned}$$

\]

Calculate page B147a columns 1 and 2

\[

$$\begin{aligned} (1)\quad &50 - 10 = 40 \\ (2)\quad &50 - 15 = 35 \\ (3)\quad &50 - 24 = 26 \\ (4)\quad &50 - 22 = 28 \\ (5)\quad &55 - 32 = 23 \\ (6)\quad &55 - 38 = 17 \\ (7)\quad &55 - 47 = 8 \\ (8)\quad &55 - 49 = 6 \end{aligned}$$

\]
</reasoning>

<answer>

No.	Problem	Answer
(2)	\(50 - 15\)	\(35\)
(3)	\(50 - 24\)	\(26\)
(4)	\(50 - 22\)	\(28\)
(5)	\(55 - 32\)	\(23\)
(6)	\(55 - 38\)	\(17\)
(7)	\(55 - 47\)	\(8\)
(8)	\(55 - 49\)	\(6\)
(9)	\(42 - 12\)	\(30\)
(10)	\(42 - 10\)	\(32\)
(11)	\(42 - 16\)	\(26\)
(12)	\(42 - 25\)	\(17\)
(13)	\(42 - 28\)	\(14\)
(14)	\(44 - 26\)	\(18\)
(15)	\(44 - 24\)	\(20\)
(16)	\(44 - 29\)	\(15\)
(17)	\(44 - 35\)	\(9\)
(18)	\(44 - 37\)	\(7\)

</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 B146b column 1

\[

$$\begin{aligned} (9)\quad &42 - 12 = 30 \\ (10)\quad &42 - 10 = 32 \\ (11)\quad &42 - 16 = 26 \\ (12)\quad &42 - 25 = 17 \\ (13)\quad &42 - 28 = 14 \end{aligned}$$

\]

Calculate page B146b column 2

\[

$$\begin{aligned} (14)\quad &44 - 26 = 18 \\ (15)\quad &44 - 24 = 20 \\ (16)\quad &44 - 29 = 15 \\ (17)\quad &44 - 35 = 9 \\ (18)\quad &44 - 37 = 7 \end{aligned}$$

\]

Calculate page B147a columns 1 and 2

\[

$$\begin{aligned} (1)\quad &50 - 10 = 40 \\ (2)\quad &50 - 15 = 35 \\ (3)\quad &50 - 24 = 26 \\ (4)\quad &50 - 22 = 28 \\ (5)\quad &55 - 32 = 23 \\ (6)\quad &55 - 38 = 17 \\ (7)\quad &55 - 47 = 8 \\ (8)\quad &55 - 49 = 6 \end{aligned}$$

\]
</reasoning>

<answer>

No.	Problem	Answer
(2)	\(50 - 15\)	\(35\)
(3)	\(50 - 24\)	\(26\)
(4)	\(50 - 22\)	\(28\)
(5)	\(55 - 32\)	\(23\)
(6)	\(55 - 38\)	\(17\)
(7)	\(55 - 47\)	\(8\)
(8)	\(55 - 49\)	\(6\)
(9)	\(42 - 12\)	\(30\)
(10)	\(42 - 10\)	\(32\)
(11)	\(42 - 16\)	\(26\)
(12)	\(42 - 25\)	\(17\)
(13)	\(42 - 28\)	\(14\)
(14)	\(44 - 26\)	\(18\)
(15)	\(44 - 24\)	\(20\)
(16)	\(44 - 29\)	\(15\)
(17)	\(44 - 35\)	\(9\)
(18)	\(44 - 37\)	\(7\)

</answer>

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