// Numbas version: finer_feedback_settings {"name": "Decimals: Addition", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Decimals: Addition", "tags": [], "metadata": {"description": "
Decimals addition algorithm. 2 and 3 digit numbers. Carrying.
", "licence": "Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International"}, "statement": "Write the following question down on paper and evaluate it without using a calculator.
\nIf you are unsure of how to do a question, click on Show steps to see the full working. Then, once you understand how to do the question, click on Try another question like this one to start again.
", "advice": "", "rulesets": {}, "extensions": [], "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"chunsumlastdigit": {"name": "chunsumlastdigit", "group": "Ungrouped variables", "definition": "mod(chunsum,10)", "description": "", "templateType": "anything", "can_override": false}, "threedigit1": {"name": "threedigit1", "group": "Ungrouped variables", "definition": "cdigs[0]/1000+cdigs[1]/100+cdigs[2]/10", "description": "", "templateType": "anything", "can_override": false}, "cunitsum": {"name": "cunitsum", "group": "Ungrouped variables", "definition": "cdigs[0]+cdigs[3]", "description": "", "templateType": "anything", "can_override": false}, "ctencarry": {"name": "ctencarry", "group": "Ungrouped variables", "definition": "floor(ctensum/10)", "description": "", "templateType": "anything", "can_override": false}, "cunitsumlastdigit": {"name": "cunitsumlastdigit", "group": "Ungrouped variables", "definition": "mod(cunitsum,10)", "description": "", "templateType": "anything", "can_override": false}, "cunitcarry": {"name": "cunitcarry", "group": "Ungrouped variables", "definition": "floor(cunitsum/10)", "description": "", "templateType": "anything", "can_override": false}, "chunsum": {"name": "chunsum", "group": "Ungrouped variables", "definition": "ctencarry+cdigs[2]+cdigs[5]", "description": "", "templateType": "anything", "can_override": false}, "ctensum": {"name": "ctensum", "group": "Ungrouped variables", "definition": "cdigs[1]+cdigs[4]+cunitcarry", "description": "", "templateType": "anything", "can_override": false}, "threedigit2": {"name": "threedigit2", "group": "Ungrouped variables", "definition": "cdigs[3]/1000+cdigs[4]/100+cdigs[5]/10", "description": "", "templateType": "anything", "can_override": false}, "ctensumlastdigit": {"name": "ctensumlastdigit", "group": "Ungrouped variables", "definition": "mod(ctensum,10)", "description": "", "templateType": "anything", "can_override": false}, "chuncarry": {"name": "chuncarry", "group": "Ungrouped variables", "definition": "floor(chunsum/10)", "description": "", "templateType": "anything", "can_override": false}, "cans": {"name": "cans", "group": "Ungrouped variables", "definition": "threedigit1+threedigit2", "description": "", "templateType": "anything", "can_override": false}, "cdigs": {"name": "cdigs", "group": "Ungrouped variables", "definition": "[0]+shuffle(3..9)", "description": "", "templateType": "anything", "can_override": false}, "cunitsumtensdigit": {"name": "cunitsumtensdigit", "group": "Ungrouped variables", "definition": "0.1*(cunitsum-cunitsumlastdigit)", "description": "", "templateType": "anything", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["cdigs", "threedigit1", "threedigit2", "cans", "cunitsum", "cunitsumlastdigit", "cunitcarry", "ctensum", "ctensumlastdigit", "ctencarry", "chunsum", "chunsumlastdigit", "chuncarry", "cunitsumtensdigit"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "gapfill", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "$\\var{threedigit1}+\\var{threedigit2} = $ [[0]]
", "stepsPenalty": "1", "steps": [{"type": "information", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "Generally, we set up $\\var{threedigit1}+\\var{threedigit2}$ with the decimal points lined up vertically so that the columns with the same place value are also lined up vertically:
\n$0$ | \n. | \n$\\var{cdigs[2]}$ | \n$\\var{cdigs[1]}$ | \n\n | $+$ | \n
$0$ | \n. | \n$\\var{cdigs[5]}$ | \n$\\var{cdigs[4]}$ | \n$\\var{cdigs[3]}$ | \n\n |
\n | \n | \n | $\\phantom{0}$ | \n\n | \n |
Note that we can pad out the decimal with zeros if we prefer:
\n$0$ | \n. | \n$\\var{cdigs[2]}$ | \n$\\var{cdigs[1]}$ | \n$\\color{red}{\\var{cdigs[0]}}$ | \n$+$ | \n
$0$ | \n. | \n$\\var{cdigs[5]}$ | \n$\\var{cdigs[4]}$ | \n$\\var{cdigs[3]}$ | \n\n |
\n | \n | \n | $\\phantom{0}$ | \n\n | \n |
Now we add the digits in the column to the far right (in this case, the thousandths column).
\nThis results in $\\var{cunitsum}$ and so we place $\\var{cunitsumlastdigit}$ under the line in this column.
\nThis results in $\\var{cunitsum}$ and so we place $\\var{cunitsumlastdigit}$ under the line in this column and carry the $1$ into the next column to the left.
\n$\\overset{\\phantom{1}}{0}$ | \n. | \n$\\overset{\\phantom{1}}{\\var{cdigs[2]}}$ | \n$\\overset{\\color{red}1}{\\var{cdigs[1]}}$ $\\overset{\\phantom{0}}{\\var{cdigs[1]}}$ | \n$\\color{green}{\\overset{\\phantom{1}}{\\var{cdigs[0]}}}$ | \n$+$ | \n
$0$ | \n. | \n$\\var{cdigs[5]}$ | \n$\\var{cdigs[4]}$ | \n$\\color{green}{\\var{cdigs[3]}}$ | \n\n |
\n | \n | \n | \n | $\\color{red}{\\var{cunitSumLastDigit}}$ | \n\n |
Now we add the digits in the next column to the left (in this case, the hundredths column).
\nThis results in $\\var{ctenSum}$ and so we place $\\var{ctenSumlastdigit}$ under the line in this column.
\nThis results in $\\var{ctenSum}$ and so we place $\\var{ctenSumlastdigit}$ under the line in this column and carry the $1$ into the next column to the left.
\n$\\overset{\\phantom{1}}{0}$ | \n. | \n$\\overset{\\color{red}{1}}{\\var{cdigs[2]}}$ $\\overset{\\phantom{1}}{\\var{cdigs[2]}}$ | \n$\\color{green}{\\overset{1}{\\var{cdigs[1]}}}$ $\\color{green}{\\overset{\\phantom{0}}{\\var{cdigs[1]}}}$ | \n$\\overset{\\phantom{1}}{\\var{cdigs[0]}}$ | \n$+$ | \n
$0$ | \n. | \n$\\var{cdigs[5]}$ | \n$\\color{green}{\\var{cdigs[4]}}$ | \n$\\var{cdigs[3]}$ | \n\n |
\n | \n | \n | $\\color{red}{\\var{ctenSumlastdigit}}$ | \n${\\var{cunitSumLastDigit}}$ | \n\n |
Now we add the digits in the next column to the left (in this case, the tenths column).
\nThis is $\\var{chunsum}$ so we place $\\var{chunsum}$ under the line in this column.
\nThis is $\\var{chunsum}$ so we place $\\var{chunsumlastdigit}$ under the line in this column and carry $\\var{chuncarry}$ into the next column to the left (which in this case is the ones column on the other side of the decimal point).
\n$\\overset{\\color{red}1}{0}$ $\\overset{\\phantom{1}}{0}$ | \n. | \n$\\color{green}{\\overset{1}{\\var{cdigs[2]}}}$ $\\color{green}{\\overset{\\phantom{1}}{\\var{cdigs[2]}}}$ | \n$\\overset{1}{\\var{cdigs[1]}}$ $\\overset{\\phantom{0}}{\\var{cdigs[1]}}$ | \n$\\overset{\\phantom{1}}{\\var{cdigs[0]}}$ | \n$+$ | \n
$0$ | \n. | \n$\\color{green}{\\var{cdigs[5]}}$ | \n$\\var{cdigs[4]}$ | \n$\\var{cdigs[3]}$ | \n\n |
\n | . | \n$\\color{red}{\\var{chunsumlastdigit}}$ | \n$\\var{ctenSumlastdigit}$ | \n${\\var{cunitSumLastDigit}}$ | \n\n |
Now we add the digits in the next column to the left (in this case, the ones column).
\nThis is just $0$ so we place $0$ under the line in this column.
\nThis is just $\\var{chuncarry}$ so we place $\\var{chuncarry}$ under the line in this column.
\n$\\color{green}{\\overset{1}{0}}$ $\\color{green}{\\overset{\\phantom{1}}{0}}$ | \n. | \n$\\overset{1}{\\var{cdigs[2]}}$ $\\overset{\\phantom{1}}{\\var{cdigs[2]}}$ | \n$\\overset{1}{\\var{cdigs[1]}}$ $\\overset{\\phantom{0}}{\\var{cdigs[1]}}$ | \n$\\overset{\\phantom{1}}{\\var{cdigs[0]}}$ | \n$+$ | \n
$\\color{green}{0}$ | \n. | \n$\\var{cdigs[5]}$ | \n$\\var{cdigs[4]}$ | \n$\\var{cdigs[3]}$ | \n\n |
$\\color{red}{\\var{chuncarry}}$ | \n. | \n$\\var{chunsumlastdigit}$ | \n$\\var{ctenSumlastdigit}$ | \n${\\var{cunitSumLastDigit}}$ | \n\n |
The answer is therefore $\\var{cans}$.
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