2)intre 28si 32 avem 29,30,31
descazutul 81
81-29= 52 estimat 81~80 29~30 80-30=50
81-30=51
81-31=50
3)a-b=43
scazatorul 28,29,30,31,32,33,34,35,36
28+43=71 estimat 28~30 43~40 30+40=70
29+43=72 estimat 29~30 43~40 30+40=70
30+43=73 estimat 30~30 43~40= 30+40=70
31+43=74
32+43=75
33+43=76 33~30 43~40 30+40=70
34+43=77 34~30 43~40 30+40=70
35+43=78 35~40 43~40 40+40=80
36+43=79 36~40 43~40 40+40=80
4)24x2=48 a douazi
100-48=52 52~50 estimat 100~100 48~50 100=50=50
5)cel mult 8 adica 1,2,3,4,5,6,7,8
27-1=26
27-2=25
27-3=24
27-4=23
27-5=22
27-6=21
27-7=20
27-8=19
6)25 estimt 30 30x7=210 estimtiv i-ar ajunge
calcul 25x7=175
7)628~600
980~1000
281~300
600+1000+300=1900 ajung 2000
calcul
628+980+281=1889
