// Numbas version: exam_results_page_options {"name": "multiplying and dividing with decimals", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"functions": {"rand": {"definition": "random(1..4)", "type": "number", "parameters": [], "language": "jme"}}, "ungrouped_variables": ["numa1", "numa2", "numb1", "numb2", "ans1", "ans2", "numc1", "numc2", "ans3", "numd1", "numd2", "ans4", "d3", "d1", "d2", "e3", "e1", "e2", "f3", "f1", "f2", "g3", "g1", "g2", "h3", "h1", "h2", "sig", "dec", "rand1", "rand2", "rand3", "rand4", "rand5"], "name": "multiplying and dividing with decimals", "tags": ["decimal", "rebel", "Rebel", "REBEL", "rebelmaths"], "advice": "
When multipling using decimals
\nWhen multipling using decimals, count how many decimal places you need to move the number to make it a whole number e.g
\n0.000054 to get to 54, we moved 6 decimal places and 0.004 to get to 4, we moved 3 decimal places
\nSo if we want to do $0.000054 \\times 0.004$ => we move the first number 6 decimal places and the second number 3 decimal places
\n=> $54 \\times 4 = 216$
\nNow since we moved 9 decimal places, altogether to the right, we move the answer 9 decimals places back to the left i.e.
\n216 becomes 0.000000216
\n\nWhen rounding to a given number of decimal places
\nWhen rounding to a given number of decimal places, do the following
\nLook at the next number after the last number of the decimal places you need to round to
\nIf the number is 5 or greater, round up, if it is than 5, leave as is; i.e.
\nround to 3 decimal places the following
\n$0.0055 = 0.006$
\n$0.0071 = 0.007$
\n\nWhen rounding to a given number of significant figures
\nWhen rounding to a given number of significant figures, do the following
\nLook at the next number after the last number of the significant figuresyou need to round to
\nIf the number is 5 or greater, round up, if it is than 5, leave as is; i.e.
\nN.B. Remember to keep the number you rounded to the significant number of places in the same unit e.g. 10's, 100's etc
\nround to 3 significant figures the following
\n$2573 = 2570$
\n$7828 = 7830$
\nround to 1 significant figures the following
\n$15 = 20$
\n$38851 = 40000$
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\nrebelmaths
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