2. solve. draw a number bond for each set.
6 + 4 =
3+7=
4 + 6 =
7 + 3 =
10 - 4 =
10 - 7=
10 -6 =
10 - 3 =
3. solve.
10 = 7+
10 =
piniitri
10 = 3 +
10 = __4
10 = 5.-
10 =
10 = 2 +
10 =
+

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4