027 lesson 17

Lesson 17 MASTERING SKILLS IN DIVISION OF WHOLE NUMBERS Objectives After this lesson, the students are expected to: ,[object Object]

follow the steps in dividing whole numbers;

master the division of whole numbers.In mastering the division operation, you should need to know all the things in this operation. When dividing numbers, it has not always given an exact quotient. This process is what we called division with remainder. 3421332408132 Division with Remainder Often when we work out a division problem, the answer is not a whole number. We can then write the answer as a whole number plus a remainder that is less than the divisor. Example 34 ÷ 5 Solution Since there is no whole number when multiplied by five produces 34, we find the nearest number without going over. Notice that 5 x 6 = 30 and 5 x 7 = 35 Hence 6 is the nearest number without going over. Now notice that 30 is 4 short of 34. We write 34 ÷ 5 = 6 R 4 quot;
6 with a remainder of 4quot;
 Example 4321 ÷ 6 Solution 720 6 | 4321 42 6 x 7 = 42 12 43 - 42 = 1 and drop down the 2 12 6 x 2 = 12 01 12 - 12 = 0 and drop down the 1 0 6 x 0 = 0 1 1 - 0 = 1 We can conclude that 4321 ÷ 6 = 720 R1 In general we write (Divisor x quotient) + Remainder = dividend Example 511 37 18932 185 37 x 5 = 185 43 189 - 185 = 4 and drop down the 3 37 37 x 1 = 37 62 43 - 37 = 6 and drop down the 2 37 37 x 1 = 37 25 62 - 37 = 25 We can conclude that Take note: the remainder may also be expressed in decimals. 18932 ÷ 37 = 511 R25 (SPECIAL TOPIC) Mental Division of Whole Numbers The process of division is just multiplication in reverse. This means that if 4 × 3 = 12 then 12 ÷ 3 = 4 and 12 ÷ 4 = 3 If you know your multiplication tables well, you should find it reasonably easy to do simple divisions in your head. For example: you want to work out 42 ÷ 7, and you remember that 6 × 7 = 42, so the answer is 6. When there is more than one operation in a question, you need to remember the order in which operations are carried out. This can be summarized by BODMAS: Brackets first O Divide Multiply Add Subtract If you see two of the same operation you just do them in the order they appear (left to right). Below are three examples of BODMAS used in a question. (a) 3 + 4 × 5 = 3 + 20 = 23(Multiply before Add) (b) 10 ÷ ( 2 + 3 ) = 10 ÷ 5 = 2(Brackets before Division) (c) 20 ÷ 2 ÷ 2 = 10 ÷ 2 = 5(do operations left to right) Bottom of Form Bottom of Form -635331-324839WORKSHEET NO. 17 NAME: ___________________________________DATE: _____________ YEAR & SECTION: ________________________RATING: ___________ ,[object Object],Question 1 -4352925321311 Use mental arithmetic to answer these questions (do not use a calculator). Then check. Top of Form (a) 16 ÷ 4_________(b) 12 ÷ 6_________(c) 15 ÷ 5_________(d) 20 ÷ 4_________(e) 18 ÷ 9_________(f) 40 ÷ 8_________(g) 36 ÷ 9_________(h) 15 ÷ 3_________(i) 64 ÷ 8_________(j) 42 ÷ 7_________(k) 24 ÷ 6_________(l) 32 ÷ 8_________ -732155-706120Use BODMAS to work out whether these statements are TRUE or FALSE. Top of Form (a) 10 ÷ 2 = 2 ÷ 10WRITE YOUR SOLUTION HERE:__________(b) 12 + 8 ÷ 2 = 10__________(c) 3 + 12 ÷ 4 = 6__________(d) 6 ÷ 2 + 3 = 6__________ -4429125236220 575487-3801745Work out the answers to the following questions (without a calculator). Top of Form (a) 3 + 4 × 8WRITE YOUR SOLUTION HERE:__________(b) 8 + 3 × 6__________(c) 8 × 6 - 4__________(d) 12 ÷ 2 + 5__________(e) 5 - 12 ÷ 3__________(f) 14 ÷ 2 + 8__________(g) 3 × 2 + 8 ÷ 4__________ Top of Form

027 lesson 17

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027 lesson 17