Grade 5 Decimal Numbers

Transcription

1 ID : ae-5-decimal-numbers [1] Grade 5 Decimal Numbers For more such worksheets visit Answer the questions (1) Which number is 0.26 less than the largest 2-digit number? (2) What is the smallest number that should be added to 4.6 to give a prime number? (3) A juice cart sells liters of grape juice on Thursday and liters more than this quantity on Friday. The following day, liters less grape juice was sold than the quantity sold on Friday. How many liters of grape juice did they sell on Saturday? (4) At a construction site, there are 16.5 loads of bricks and the total weight of all the loads together is kg. Find the weight of one load? (5) What number do you get by adding 4 Thousandths and 39 Thousandths together to 43 Tens? (6) Write the number five hundredths in decimal form. (7) A snail crawls 76 cm in 50 minutes. It crawls another 78 cm in 52 minutes. How many metres does it crawl in total? (8) Hassan's father gave him Dhs139 to spend. He spent Dhs48.80 to buy some toys and Dhs37.59 to buy some books. How much money is he left with in the end? (9) What do you get when you multiply 6.0 and 3.29? (10) How many pieces do we get when we cut a thread of length 21 meters into 1.5 meter long pieces? (11) What is the value of ? (12) What is the smallest number that should be added to to give an even number? (13) A snail crawls meters in 4.6 hours. How much distance can it crawl in ten hours? (14) What are you left with when you take away one tenths four times from 1? Choose correct answer(s) from the given choices (15) Solve the following A) = a b c d C) 10 = a b c d B) 2.37 x = a b. 4.2 c d D) = a b c d

2 ID : ae-5-decimal-numbers [2] 2017 Edugain ( All Rights Reserved Many more such worksheets can be generated at

3 Answers ID : ae-5-decimal-numbers [3] (1) We know that the largest 2-digit number is 99 (a whole number). Therefore, 0.26 less than 99 can be found by subtracting the number 0.26 from 99. Let us first convert the whole number 99 into its decimal form. In decimal form, 99 can be written as We know that the decimals with the same number of decimal places are called like decimals. Now, our task is to subtract the like Decimal 0.26 from Let us subtract them starting from the hundredths place and carry over, if needed. We should keep in mind that the decimal point in the answer must be placed at the same place as in the subtrahend. Hundred Ten Thousands Hundreds Tens Ones. Tenth Hundredth Thousands Thousands Step 5 Hence, the number that is 0.26 less than the largest 2-digit number is (2) 0.4 We know that 4.6 is not a prime number. On close observation, we find that the nearest prime number higher than 4.6 is 5. Therefore, the smallest number that should be added to 4.6 to make it prime = = 0.4.

4 (3) liters ID : ae-5-decimal-numbers [4] Quantity of grape juice sold on Thursday = liters Quantity of grape juice sold on next day (i.e. Friday) = = liters Quantity of grape juice sold on the day following Friday, i.e., Saturday = = liters Hence, liters of cranberry juice was sold on Saturday. (4) kg The number of loads of bricks = 16.5 Total weight of all the loads together = kg In order to find the weight of one load, we need to divide the total weight by the number of loads. Therefore, the weight of one load is = kg.

5 (5) ID : ae-5-decimal-numbers [5] Let us first convert the number names into numerals: 4 Thousandths = = Thousandths = = Tens = = 430 Let us first add the decimal numbers as below: Lakhs Thousands Ones Tenths Hundredths Thousandths Ten thousandths TL L TTH TH H T O. (1/10) (1/100) (1/1000) (1/10000) Total Legend: TL - Ten Lakhs, L - Lakhs, TTH - Ten Thousands, TH - Thousands, H - Hundreds, T - Tens, O - Ones. Let us now add the decimal numbers to the whole number: Lakhs Thousands Ones Tenths Hundredths Thousandths Ten thousandths TL L TTH TH H T O. (1/10) (1/100) (1/1000) (1/10000) Total Therefore, by adding 4 Thousandths and 39 Thousandths together to 43 Tens, we get (6) 0.05 Let us first write the given number name as a fraction: Converting the fraction into a decimal number, we get: = 0.05

6 (7) 1.54 m. ID : ae-5-decimal-numbers [6] The total distance (in cm) the snail crawls: 76 cm + 78 cm = 154 cm Now, let us convert the distance 154 cm (centimetres) into meters. We know that: 100 cm = 1 m Therefore, 154 cm = 154 m = 1.54 m 100 Hence, the snail crawls 1.54 m in total.

7 (8) Dhs52.61 ID : ae-5-decimal-numbers [7] The amount of money Hassan's father gave him = Dhs139 The amount of money Hassan spent on buying toys = Dhs48.80 The amount of money Hassan spent on buying books = Dhs37.59 Let us add the amount of money he spent on buying toys and books to find his total expense: Toys Books = Dhs48.80 = Dhs37.59 Total expense = Dhs86.39 Step 5 In order to find the amount left with him, we need to subtract the amount Hassan spent from the amount his father gave him. Step 6 Before subtracting the two numbers, let us make sure they are written as Like Decimals. We know that the decimals with the same number of decimal places are called Like Decimals. Thus, let us write Dhs139 as Dhs and subtract Dhs86.39 from it. Step 7 Let us subtract the amount Hassan spent (Dhs86.39) from the amount his father gave (Dhs139), digit by digit. The numbers must be placed according to their place values. The greater number of the two numbers must be placed on top and the smaller one below it. Thousands Hundreds Tens Ones. Tenth Hundredth Step 8 Hence, Hassan is left with Dhs52.61.

8 (9) ID : ae-5-decimal-numbers [8] In order to multiply the two decimal numbers, let us first find out the position of the decimal point in the final product. Let us first count the number of decimal places in both the multiplicands. The total number of decimal places in the product will be the sum of the number of decimal places in both the multiplicands. In the number 6.0, there is 1 decimal place and in 3.29, there are 2 decimal places. Hence, there will be a total of 3 decimal places in the final product. Now, let us multiply the two numbers just like whole numbers, and in the final product, place the decimal point such that there are 3 decimal places (i.e. after 3 places from the right): x Step 5 Now, put the decimal point after three places from right. Therefore, = (10) 14 Total length of the thread = 21 meters Length of one piece of the thread = 1.5 meters Number of pieces of the thread = Total length of the thread Length of one piece of the thread 21 = 1.5 = 14 Hence, we get 14 pieces of the thread.

9 (11) 8.66 ID : ae-5-decimal-numbers [9] In order to do the given division, we will cancel the decimals first. Therefore, = Now, simply dividing the given fraction, we get 8.66 as the answer. (12) 0.65 (13) 4.3 The total length a snail crawls in 4.6 hours = metres The length it can crawl in 1 hour = = 0.43 metres So, the length it can crawl in 10 hours = = 4.3 metres Therefore, the snail can crawl 4.3 metres in ten hours. (14) 0.6 If you look at the question carefully, we will notice: 1 one tenths = 10 and four times of 1 10 = 4 10 = 0.4 Now, taking one tenths four times from 1, we get: = 0.6 Hence, we are left with 0.6 if we take away one tenths four times from 1. (15) A) c B) b. 4.2 C) c D) d