☰ Contents · Computing

Using mathematical operations and functions in MS Excel

Lessons 21–22 · 2 lessons · B. Boltayev, A. Azamatov, A. Asqarov, M. Sodiqov, G. Azamatova. Fundamentals of Informatics and Computer Technology, Grade 8. Second edition. “O‘zbekiston milliy ensiklopediyasi” State Scientific Publishing House, Tashkent, 2015
22

Review: mathematical operations and functions in MS Excel

Textbook: p. 102
GoalApplies functions and operations in mixed tasks: units, prices, perimeter, integer part and remainder.
New words
unit conversion: changing a quantity from one unit to another, e.g. km/h to m/s · birlikni o‘tkazishinteger part: the whole-number part of a quotient · butun qismremainder: what is left after dividing as far as possible with whole numbers · qoldiqchecking: testing a formula on numbers whose result you know · tekshirish
Explanation

In a review lesson we first turn a problem into a formula on paper and then move it to the sheet. Enter the input data in separate cells and let the result be calculated with cell addresses, so that if the data changes the result changes too. Units must match: to convert km/h to m/s we divide by 3.6, since 1 km/h = 1000 m : 3600 s; when comparing prices we bring them all to the same amount (for example 1 kg). To compare two quantities we use IF and display the result in words. When dividing whole numbers, the whole part of the quotient is INT(A1/B1) and the remainder is MOD(A1; B1). To check, test the formula on numbers whose answer you know.

Worked examples
Comparing prices: shop A sells rice at 14,000 so‘m per kg (A1), shop B at 6,500 so‘m per 500 g (B1). In shop B 1 kg = 2 · 6,500 = 13,000 so‘m. =IF(A1<2*B1; "A cheaper"; "B cheaper") → "B cheaper".
Time: A1 = 135 minutes. Whole hours: =INT(A1/60) → 2; minutes left: =MOD(A1; 60) → 15. Check: 2 · 60 + 15 = 135.
Class activity

“Problem – formula – sheet”: a group chooses a practical problem (for example the length and cost of a yard fence), plans the input cells and formulas on the board, then tests them in the sheet.

Practice
1
A rectangular yard is 25 m × 18 m (A1, B1), and 1 m of fence costs 40,000 so‘m (C1). Write the formulas for the fence length and cost and find their values.
2
How many m/s is 90 km/h? Write the formula.
3
A1 = 200 seconds. How many whole minutes and how many seconds is that? Write the formulas.
4
Why must prices be brought to the same amount (for example 1 kg) before comparing them?