MULTIPLICATION 



4001 



MUMMY 



than division, and is much more pleasing. Chil- 

 dren enjoy testing their work by this method. 



628xl37 = n 



\\ork Tet 



628 628 



137 137 



4396 56 



1884 140 



628 4200 



86036 240 



600 



18000 



800 



2000 



60000 



86036 



In the early days of the work, drawing on 

 cross-section paper may be used to great advan- 

 tage to clarify the multiplication and to test 

 the work. For example, 28X17Xn: 



28 



17 

 200 = 10X20 



80 = 10X8 

 140 = 7X20 



56 = 7X8 

 476 



The drawing (Fig. 2) shows all the partial 

 products as areas. 



FIG. 2 



One child may test another's work by draw- 

 in IT. or one may work the problem by drawing, 

 and another test it by numbers. The cross- 

 section paper is most valuable in this work. 

 Testing in the two ways here suggested adds 

 zest to the work, arouses a general interest in 

 each individual's work, and brings about a feel- 

 ing of responsibility on each student's part that 

 is not felt when he must ask the teacher, or 

 mother or father, for approval of his answer. 

 For method of proof refer to DIVISIBILITY OF 



KRs, subhead Coating out of ff. 

 Problems. 1. Mollie spends 6< a day; how 

 much does she spend in 7 days? 8 days? 11 



2 Home-made bread is 12* a loaf. What will 

 3 loaves cost? 5 loaves? 8 loaves? 

 251 



3. Eggs are selling 52tf per dozen. How much 

 will a woman get who sells 16 dozen? 



4. How many square feet in a floor 24 feet 

 long and 18 feet wide? At 12 per square foot 

 what will it cost to floor it? 



5. A farmer has 27 acres of onions and the 

 yield is 516 bushels per acre. What is the en- 

 tire yield? 



Solution of Problem 4 

 Length = 24 feet 

 Width = 18 feet 

 Number of square feet = 24 X 18 = 432 



Solution of Problem 5 



Number bushels on 1 acre = 51 6 



Number bushels on 27 acres = 27x516 = 13932 



Some Interesting Quick Multiplication* 



(a) 65 (b) 95 (c) 75 



X65 X95 X76 



4225 9025 5625 



Explanation. 5X5 is 25. Add 1 to the tens 

 of the multiplier and take the product of the 

 tens. In (a) this product is 7X6, or 42; in (b) 

 10X9, or 90; in (c) 8X7, or 56. 



(d) 78 



72 



5616 



(e) 84 



86 



7224 



(f) 49 



41 



2009 



Explanation. Take product of the units: 

 2X8=16, 6X4=24, 1X9=9. Add 1 to the tens 

 of the multiplier and take product of the tens: 

 in (d) 8X7=56, in (e) 9X8=72, in (f) 5X4=20. 



(gr) 105 



106 



11025 



(J) 205 



206 

 41016 



(h) 



107 

 103 



(I) 



11021 



(k) 307 



303 



so 



The same explanation holds in these last six 

 as above; for example, in (k) the product of 

 the units is 3X7, or 21; add 1 to the tens of 

 multiplier and the product of the tens is 

 31X30, or 930. The reason for this is' evident 

 in the following: 75X75= (70X70) + (5X70+ 

 5X70)+5X5. But 5X70+5X70=10X70 and 

 70X70+10X70=80X70, which we get by add- 

 inn / to the tens of the multiplier. It is seen 

 also in the following: 87X83=(80X80) + (7X 

 80+3X80)+3X7,which=80X80+ 10X80+3X7, 

 \v| 11 .h-90X80+3X7. 



Children and older students enjoy this i 

 play with numbers, and like to mystify others 

 with their seeming magic in performing rapid 

 multiplications. \ 



MUMMY, mum' t, an embalmed body, pre- 

 served by the process used by the Egyptians 

 in preparing their dead for burial. The bodies 



