 #   ### Sample

Multiply by 5: Multiply by 10 and divide by 2. (using 27 x 5) 27 x 5 = 27 x 10 = 270 / 2 (270/2 ) = 135
Multiply by 6: Sometimes multiplying by 3 and then 2 is easy. 27 x 6 = 27 x 3 = 81 x 2 = 162
Multiply by 9: Multiply by 10 and subtract the original number. 27 x 9 = 27 x 10 = 270 – 27 = 243
Multiply by 12: Multiply by 10 and add twice the original number. 27 x 12 = 27 x 10 = 270 + 54 = 324
Multiply by 13: Multiply by 3 and add 10 times original number. 27 x 13 = 27 x 3 = 81 + 270 = 351
Multiply by 14: Multiply by 7 and then multiply by 2 27 x 14 = 27 x 7 = 189 x 2 = 378
Multiply by 15: Multiply by 10 and add 5 times the original number, (using 25 x 15) 25 x 15 = 25 x 10 = 250 + 75 = 325
Multiply by 16: Multiply by 8 and then x by 2. 27 x 16 = 27 x 8 = 216 x 2 = 432
Multiply by 17: Multiply by 7 and add 10 times original number. 27 x 17 = 27 x 7 = 189 + 270 = 459
Multiply by 18: Multiply by 20 and subtract twice the original number 27 x 18 = 27 x 20 = 540 – 54 = 486
Multiply by 19: Multiply by 20 and subtract the original number. 25 x 20 = 500 - 25 = 475
Multiply by 24: Multiply by 8 and then multiply by 3.
Multiply by 27: Multiply by 30 and subtract 3 times the original number
Multiply by 45: Multiply by 50 and subtract 5 times the original number
Multiply by 90: Multiply by 9 (as above) and put a zero on the right.
Multiply by 98: Multiply by 100 and subtract twice the original number.
Multiply by 99: Multiply by 100 and subtract the original number.

## Calculate a Tip

Tally the restaurant or hotel bill total (round it up) \$154.70 rounded is \$ \$155 = 1% = \$1.55 and multiply by the amount you wish to tip

10% would be \$15.50

20% - \$15.50 x 2 = \$31.00

If you need to leave a 15% tip,

here is the easy way to do it.

Work out 10% (divide the number by 10) – then add that number to half its value and you have your answer:

10% of \$155.00 = 15.50 plus half of \$15.50 = 7.25

= \$15.50 + \$7.25 tip 15% = \$22.75 (just give a \$25)

Sample Restaurant bill \$254.00 Tip 15% = 10% is \$25.40 plus half of \$25.40 = \$12.70 Add \$25.40 and \$12.70 = \$38.10

will you round it up (staff rely on tips)

### Large Group Sharing a bill

First rule all pay the same even if someone had desert and others did not (far to hard to re-calculate)

Take the bill divide it by the number at the table

Say you bill was \$500.00 for 6 people divide \$500 by 6 = \$83.33 each pay

everyone round up to \$90 and the excess is a small tip for the staff! (\$40 tip) Here is a useful resource site in the USA that looks at educating STEM & STEAM Units USA have two components both the same but one set includes Art

STEM Science, Technology, Engineering and Math or STEAM Science, Technology, Engineering, Arts and Math fields

Here is a link to Calculator resources in the Everyday Financial Calculators you can use on-line (USA based) Every Day Financial Calculator Various on line calculators Simple Calculators (thanks to Megan & Mrs Anna Jones) ### In Australia we also have STEM as a curriculum unit however STEM covers Engineering but in WA Schools we use Design Technology rather than Engineering; Design Technology uses woodwork, metalwork robotics etc. to cover an introduction to the Engineering field.

This page is part of the STEM or STEAM Environment please take a closer look at the other pages

## Science Technology Engineering Art Mathematics (you are here) ## http://www.sosmath.com/algebra/fraction/frac8/frac8.html

 Insert fraction into word documents MATH118 Creating maths fractions MIS107 Maths Tricks MIS113 State of a Village MATH100 Quick Square MATH101 Eleven Time Trick MATH102 Multiply by Four MATH103 Multiply by Five MATH104 Multiply by Nine MATH105 Multiply Anything MATH106 Calculate a Tip MATH107 Tough Multiplication MATH108 Dividing Large Numbers MATH109 Subtracting from 1,000 MATH110 Assorted Multiplication Rules MATH120 Percentages Maths in Minutes Quizzes Answers MATH111 Level 1 White Quiz Q MATH111 Level 1 White Quiz S MATH112 Level 2 Yellow Quiz Q MATH112 Level 2 Yellow Quiz S MATH113 Level 3 Red Quiz Q MATH113 Level 3 Red Quiz S MATH114 Level 4 Green Quiz Q MATH114 Level 4 Green Quiz S MATH115 Level 5 Gold Quiz Q MATH115 Level 5 Gold Quiz S MATH117 Division of Fractions MATH118 Creating maths fractions

#### Have fun online with ### or have fun with calculators at Piggly All Exam Papers     Email Peter Faulks Page created 27th March 2014

Page last updated 23rd June 2018