Kategorier: Alla - units - addition

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Elementary Mathematics

Mental math techniques can simplify the process of addition, making it faster and more intuitive. One method involves adding numbers from the left, starting with the tens and then moving to the units.

Elementary Mathematics

Mental Mathematics: Addition

Using Compatible Numbers

These are numbers whose sums are easy to calculate mentally

300+20=320
100+200=300
50+50=100
130+70=200
130+50+70+20+50

Trading Off

17+36
(add 3 to make a mulitiple of 10) 17+3=20

(subtract 3 to compensate for the 3 that was added) 36-3=33

(add the two numbers) 20+33=53

Breaking Up and Bridging

47+16
(add the first number to the tens in the second number) 47+10=57

(add this sum to the units in the second number) 57+6=63

Adding from the left

57+26
(add the units) 7+6=13

(add the two sums) 80+13=93

(add the tens) 50+30=80