Solving Exercise 3 Page 74 Math 4 Textbook

Guidance to solve exercise 3 on page 74 of Math 4 textbook

Problem:
Calculate with utmost convenience:
a) 142 x 12 + 42 x 18;                  b) 49 x 365 - 39 x 365;                                  c) 4 x 18 x 25

Solution Method:
- For part a): Apply the calculation method: a x b + a x c = a x (b + c)
- For part b): Apply the calculation method: a x c - b x c = (a - b) x c
- For part c): Apply the associative property of multiplication: a x b x c = a x (b x c) = (a x b) x c, to group the factors whose product is a multiple of ten together, then multiply with the remaining number. 

Answer:
a) 142 x 12 + 42 x 18                          b) 49 x 365 - 39 x 365                     c) 4 x 18 x 25
= 142 x (12 + 18)                                      = (49 - 39) x 365                             = 18 x (4 x 25)
= 142 x 30 = 4260                                    = 10 x 365 = 3650                           = 18 x 100 = 1800

Part solution to exercise 74 math 4, Practice includes 4 exercises, Next, solve exercise 3 on page 74 Math 4 textbook. Mytour has hints and detailed solution methods for Solving Exercise 1 Page 74 Math 4 Textbook, Solving Exercise 2 Page 74 Math 4 Textbook, Solving Exercise 4 Page 74 Math 4 Textbook and Solving Exercise 5 Page 74 Math 4 Textbook, students need to grasp the knowledge of this lesson.